MANAGING DEVICES FOR VIRTUAL TELEPRESENCE

Abstract

Techniques and systems are provided for capturing images by a first device. For instance, a process can include obtaining a first image from a first camera, the first image being associated with a first capture time based on a first clock; mapping the first capture time to a second clock to obtain a second capture time, the second capture time based on a second clock, and wherein the second clock is based on a network time; associating the second capture time with the first image; obtaining a second image from a second camera of another device, the second image including a third capture time based on the second clock; determining phase delta information based on a time difference between the second capture time and the third capture time; and outputting the phase delta information to adjust a next capture time of at least one of the first or second camera.

Description

FIELD

This application is related to content for extended reality (XR) systems. For example, aspects of the application relate to systems and techniques for managing devices for virtual telepresence.

BACKGROUND

Extended reality (XR) technologies can be used to present virtual content to users, and/or can combine real environments from the physical world and virtual environments to provide users with XR experiences. The term XR can encompass virtual reality (VR), augmented reality (AR), mixed reality (MR), and the like. XR systems can allow users to experience XR environments by overlaying virtual content onto images of a real-world environment, which can be viewed by a user through an XR device (e.g., a head-mounted display (HMD), extended reality glasses, or another device). For example, an XR device can display a virtual environment to a user. The virtual environment is at least partially different from the real-world environment in which the user is in. The user can generally change their view of the virtual environment interactively, for example by tilting or moving the XR device (e.g., the HMD or other device).

An XR system can include a “see-through” display that allows the user to see their real-world environment based on light from the real-world environment passing through the display. In some cases, an XR system can include a “pass-through” display that allows the user to see their real-world environment, or a virtual environment based on the real-world environment, using a view of the environment being captured by one or more cameras and displayed on the display. “See-through” or “pass-through” XR systems can be worn by users while the users are engaged in activities in the real-world environment.

In some cases, XR systems may be used to enhance telepresence experiences. Telepresence technologies may allow a person to perform actions and/or have experiences, such as a collaborative experience with other persons, at a remote and/or virtual locations as if the person were physically present with the other persons. As an example, users may be represented in a virtual space as an animated avatar which may mimic movements and/or expressions of their representative user. A particular user may view the remote/virtual locations from a perspective of the avatar, for example, via an XR display device, such as a head mounted display (HMD) or mobile device. In some cases, to help allow for a more seamless telepresence experience using HMDs, it may be beneficial to reduce a weight and bulkiness of the HMD such that the HMD may resemble ordinary eyeglasses. In some cases, to reduce the weight and bulkiness of such HMDs, certain sensors may be omitted, as compared to bulkier and/or heavier head-mounted displays. In some cases, external sensors, such as a companion device, companion camera, audio sensors, any combination thereof, and the like, may be used along with such relatively lightweight head-mounted displays. In some cases, techniques for managing and/or integrating such companion devices for virtual telepresence may be useful.

SUMMARY

The following presents a simplified summary relating to one or more aspects disclosed herein. Thus, the following summary should not be considered an extensive overview relating to all contemplated aspects, nor should the following summary be considered to identify key or critical elements relating to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the following summary presents certain concepts relating to one or more aspects relating to the mechanisms disclosed herein in a simplified form to precede the detailed description presented below.

In one illustrative example, an augmented reality apparatus is provided. The apparatus includes a memory and a processor coupled to the memory. The at least one processor is configured to: obtain a first image from a first camera, the first image being associated with a first capture time based on a first clock; map the first capture time to a second clock to obtain a second capture time, wherein the second capture time is based on a second clock, and wherein the second clock is based on a network time; associate the second capture time with the first image; obtain a second image from a second camera of a device, the second image including a third capture time based on the second clock; determine phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; and output the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

In another example, a method for image capture by a first device is provided. The method includes: obtaining a first image from a first camera, the first image being associated with a first capture time based on a first clock; mapping the first capture time to a second clock to obtain a second capture time, wherein the second capture time is based on a second clock, and wherein the second clock is based on a network time; associating the second capture time with the first image; obtaining a second image from a second camera of a second device, the second image including a third capture time based on the second clock; determining phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; and outputting the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

As another example, a non-transitory computer-readable medium is provided. The non-transitory computer-readable medium has stored thereon instructions that, when executed by at least one processor, cause the at least one processor to: obtain a first image from a first camera, the first image being associated with a first capture time based on a first clock; map the first capture time to a second clock to obtain a second capture time, wherein the second capture time is based on a second clock, and wherein the second clock is based on a network time; associate the second capture time with the first image; obtain a second image from a second camera of a second device, the second image including a third capture time based on the second clock; determine phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; and output the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

In another example, an apparatus for image capture is provided. The apparatus includes: means for obtaining a first image from a first camera, the first image being associated with a first capture time based on a first clock; means for mapping the first capture time to a second clock to obtain a second capture time, wherein the second capture time is based on a second clock, and wherein the second clock is based on a network time; means for associating the second capture time with the first image; obtaining a second image from a second camera of a second device, the second image including a third capture time based on the second clock; means for determining phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; and means for outputting the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

In some aspects, the apparatus can include or be part of an extended reality device (e.g., a virtual reality (VR) device, an augmented reality (AR) device, or a mixed reality (MR) device), a mobile device (e.g., a mobile telephone or other mobile device), a wearable device (e.g., a network-connected watch or other wearable device), a personal computer, a laptop computer, a server computer, a television, a video game console, or other device. In some aspects, the apparatus further includes at least one camera for capturing one or more images or video frames. For example, the apparatus can include a camera (e.g., an RGB camera) or multiple cameras for capturing one or more images and/or one or more videos including video frames. In some aspects, the apparatus includes a display for displaying one or more images, videos, notifications, or other displayable data. In some aspects, the apparatus includes a transmitter configured to transmit data or information over a transmission medium to at least one device. In some aspects, the processor includes a central processing unit (CPU), a graphics processing unit (GPU), a neural processing unit (NPU), or other processing device or component.

This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification of this patent, any or all drawings, and each claim.

The foregoing, together with other features and examples, will become more apparent upon referring to the following specification, claims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Illustrative examples of the present application are described in detail below with reference to the following figures:

FIG. 1 is a block diagram illustrating an architecture of an image capture and processing system, in accordance with aspects of the present disclosure.

FIG. 2 is a diagram illustrating an architecture of an example extended reality (XR) system, in accordance with some aspects of the disclosure.

FIG. 3A-3D and FIG. 4 are diagrams illustrating examples of neural networks, in accordance with some examples.

FIG. 5 illustrates an XR system including companion devices, in accordance with aspects of the present disclosure.

FIG. 6 is a block diagram illustrating a technique 600 for managing clock synchronization for devices for virtual telepresence, in accordance with aspects of the present disclosure.

FIG. 7A is an image showing a portion of the face occluded by a HMD, in accordance with aspects of the present disclosure.

FIG. 7B illustrates images obtained by eye tracking cameras, in accordance with aspects of the present disclosure.

FIG. 8 is a block diagram illustrating a technique for providing labeled training data for segmenting a HMD from images of a user wearing the HMD, in accordance with aspects of the present disclosure.

FIG. 9 is a block diagram illustrating a mesh estimation network for generating a model of a user for telepresence using multiple devices, in accordance with aspects of the present disclosure.

FIG. 10 is a flow diagram illustrating a process for managing devices for virtual telepresence, in accordance with aspects of the present disclosure.

FIG. 11 is a flow diagram illustrating a process for generating a full body model, in accordance with aspects of the present disclosure.

FIG. 12A is a perspective diagram illustrating a head-mounted display (HMD), in accordance with some examples.

FIG. 12B is a perspective diagram illustrating the head-mounted display (HMD) of FIG. 12A, in accordance with some examples.

FIG. 13A is a perspective diagram illustrating a front surface of a mobile device that can display XR content, in accordance with some examples.

FIG. 13B is a perspective diagram illustrating a rear surface of a mobile device 950, in accordance with aspects of the present disclosure.

FIG. 14 is a diagram illustrating an example of a system for implementing certain aspects of the present technology.

DETAILED DESCRIPTION

Certain aspects and examples of this disclosure are provided below. Some of these aspects and examples may be applied independently and some of them may be applied in combination as would be apparent to those of skill in the art. In the following description, for the purposes of explanation, specific details are set forth in order to provide a thorough understanding of subject matter of the application. However, it will be apparent that various examples may be practiced without these specific details. The figures and description are not intended to be restrictive.

The ensuing description provides illustrative examples only, and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing the illustrative examples. It should be understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the application as set forth in the appended claims.

Extended reality (XR) systems or devices can provide virtual content to a user and/or can combine real-world or physical environments and virtual environments (made up of virtual content) to provide users with XR experiences. The real-world environment can include real-world objects (also referred to as physical objects), such as people, vehicles, buildings, tables, chairs, and/or other real-world or physical objects. XR systems or devices can facilitate interaction with different types of XR environments (e.g., a user can use an XR system or device to interact with an XR environment). XR systems can include virtual reality (VR) systems facilitating interactions with VR environments, augmented reality (AR) systems facilitating interactions with AR environments, mixed reality (MR) systems facilitating interactions with MR environments, and/or other XR systems. Examples of XR systems or devices include head-mounted displays (HMDs), smart glasses, among others. In some cases, an XR system can track parts of the user (e.g., a hand and/or fingertips of a user) to allow the user to interact with items of virtual content.

AR is a technology that provides virtual or computer-generated content (referred to as AR content) over the user's view of a physical, real-world scene or environment. AR content can include virtual content, such as video, images, graphic content, location data (e.g., global positioning system (GPS) data or other location data), sounds, any combination thereof, and/or other augmented content. An AR system or device is designed to enhance (or augment), rather than to replace, a person's current perception of reality. For example, a user can see a real stationary or moving physical object through an AR device display, but the user's visual perception of the physical object may be augmented or enhanced by a virtual image of that object (e.g., a real-world car replaced by a virtual image of a DeLorean), by AR content added to the physical object (e.g., virtual wings added to a live animal), by AR content displayed relative to the physical object (e.g., informational virtual content displayed near a sign on a building, a virtual coffee cup virtually anchored to (e.g., placed on top of) a real-world table in one or more images, etc.), and/or by displaying other types of AR content. Various types of AR systems can be used for gaming, entertainment, and/or other applications.

In some cases, there may be a preference to use relatively lightweight AR HMDs that may appear closer to regular glasses as compared to relatively more bulky VR HMDs. In some cases, such relatively lightweight AR HMDs may omit certain sensors from the HMDs to help reduce weight and/or bulkiness. For example, body and/or pose tracking cameras may be omitted from relatively lightweight AR HMDs, as compared to more fully featured VR HMD devices which may be bulky and/or heavier. To allow such relatively lightweight AR HMDs to be used with fully body avatars, for example for virtual telepresence scenarios, the relatively lightweight AR HMDs may be used along with a companion device, such as a mobile device, telepresence cameras, etc., to obtain body and pose information. To obtain body and pose information, the companion devices may be managed to coordinate the information obtained by the various devices.

Systems, apparatuses, electronic devices, methods (also referred to as processes), and computer-readable media (collectively referred to herein as “systems and techniques”) are described herein for managing multiple devices for virtual telepresence operations. Multiple digital devices may operate using different unsynchronized clocks, which may make generating coherent 3D representations using images captured by the multiple digital devices difficult. In some cases, networked devices may establish a common clock, or network time, to allow the networked devices to precisely time their transmissions to avoid interference. In some cases, this network time may be mapped to another clock used by the device to capture images. A first captured image may then be tagged with the network time as the first capture time. For instance, the first capture time (based on the network time) can be included as a timestamp that can be provided (e.g., transmitted, streamed, etc.) in or with the frame data of the first captured image.

The first capture time may be compared to a second capture time associated with a second captured image from another device. A phase delta may be determined, where the phase delta indicates an amount of time a device may delay or accelerate capture of a next image, for example, by adjusting a vertical blanking period of the camera.

In some cases, a head model may be generated in part based on images captured by a companion device external to the HMD. In such cases, portions of the head around the eyes may be occluded by the HMD. To provide information about such portions of the head, it may be useful to merge image information for the occluded portions obtained by eye tracking cameras of the HMD. In some cases, where multiple devices are used, the cameras of the multiple devices may not be rigidly mounted with respect to the HMD as would be the case with an HMD with integrated body and/or pose tracking cameras. Additionally, as the cameras are not rigidly mounted, a pose of the cameras may vary, making integrating a model of a head and portions of the head occluded by the HMD challenging. In some cases, one or more machine learning models may be used to estimate a head model along with camera poses. For example, a first set of features may be detected in images taken from the companion device. A second set of features may also be detected in images from the HMD. In some cases, the sets of features may be extracted by portions of the machine learning model. The two sets of features may be concatenated (e.g., appended). Another portion of the machine learning model may then generate pose information and a head mesh based on the concatenated sets of features. This head mesh may be merged with a headless body mesh that may be generated based on the images captured by the companion device to generate a full body model. The full body model may be used, for example, by a telepresence application, to generate an avatar.

Various aspects of the application will be described with respect to the figures.

FIG. 1 is a block diagram illustrating an architecture of an image capture and processing system 100. The image capture and processing system 100 includes various components that are used to capture and process images of scenes (e.g., an image of a scene 110). The image capture and processing system 100 can capture standalone images (or photographs) and/or can capture videos that include multiple images (or video frames) in a particular sequence. In some cases, the lens 115 and image sensor 130 can be associated with an optical axis. In one illustrative example, the photosensitive area of the image sensor 130 (e.g., the photodiodes) and the lens 115 can both be centered on the optical axis. A lens 115 of the image capture and processing system 100 faces a scene 110 and receives light from the scene 110. The lens 115 bends incoming light from the scene toward the image sensor 130. The light received by the lens 115 passes through an aperture. In some cases, the aperture (e.g., the aperture size) is controlled by one or more control mechanisms 120 and is received by an image sensor 130. In some cases, the aperture can have a fixed size.

The one or more control mechanisms 120 may control exposure, focus, and/or zoom based on information from the image sensor 130 and/or based on information from the image processor 150. The one or more control mechanisms 120 may include multiple mechanisms and components; for instance, the control mechanisms 120 may include one or more exposure control mechanisms 125A, one or more focus control mechanisms 125B, and/or one or more zoom control mechanisms 125C. The one or more control mechanisms 120 may also include additional control mechanisms besides those that are illustrated, such as control mechanisms controlling analog gain, flash, HDR, depth of field, and/or other image capture properties.

The focus control mechanism 125B of the control mechanisms 120 can obtain a focus setting. In some examples, focus control mechanism 125B store the focus setting in a memory register. Based on the focus setting, the focus control mechanism 125B can adjust the position of the lens 115 relative to the position of the image sensor 130. For example, based on the focus setting, the focus control mechanism 125B can move the lens 115 closer to the image sensor 130 or farther from the image sensor 130 by actuating a motor or servo (or other lens mechanism), thereby adjusting focus. In some cases, additional lenses may be included in the image capture and processing system 100, such as one or more microlenses over each photodiode of the image sensor 130, which each bend the light received from the lens 115 toward the corresponding photodiode before the light reaches the photodiode. The focus setting may be determined via contrast detection autofocus (CDAF), phase detection autofocus (PDAF), hybrid autofocus (HAF), or some combination thereof. The focus setting may be determined using the control mechanism 120, the image sensor 130, and/or the image processor 150. The focus setting may be referred to as an image capture setting and/or an image processing setting. In some cases, the lens 115 can be fixed relative to the image sensor and focus control mechanism 125B can be omitted without departing from the scope of the present disclosure.

The exposure control mechanism 125A of the control mechanisms 120 can obtain an exposure setting. In some cases, the exposure control mechanism 125A stores the exposure setting in a memory register. Based on this exposure setting, the exposure control mechanism 125A can control a size of the aperture (e.g., aperture size or f/stop), a duration of time for which the aperture is open (e.g., exposure time or shutter speed), a duration of time for which the sensor collects light (e.g., exposure time or electronic shutter speed), a sensitivity of the image sensor 130 (e.g., ISO speed or film speed), analog gain applied by the image sensor 130, or any combination thereof. The exposure setting may be referred to as an image capture setting and/or an image processing setting.

The zoom control mechanism 125C of the control mechanisms 120 can obtain a zoom setting. In some examples, the zoom control mechanism 125C stores the zoom setting in a memory register. Based on the zoom setting, the zoom control mechanism 125C can control a focal length of an assembly of lens elements (lens assembly) that includes the lens 115 and one or more additional lenses. For example, the zoom control mechanism 125C can control the focal length of the lens assembly by actuating one or more motors or servos (or other lens mechanism) to move one or more of the lenses relative to one another. The zoom setting may be referred to as an image capture setting and/or an image processing setting. In some examples, the lens assembly may include a parfocal zoom lens or a varifocal zoom lens. In some examples, the lens assembly may include a focusing lens (which can be lens 115 in some cases) that receives the light from the scene 110 first, with the light then passing through an afocal zoom system between the focusing lens (e.g., lens 115) and the image sensor 130 before the light reaches the image sensor 130. The afocal zoom system may, in some cases, include two positive (e.g., converging, convex) lenses of equal or similar focal length (e.g., within a threshold difference of one another) with a negative (e.g., diverging, concave) lens between them. In some cases, the zoom control mechanism 125C moves one or more of the lenses in the afocal zoom system, such as the negative lens and one or both of the positive lenses. In some cases, zoom control mechanism 125C can control the zoom by capturing an image from an image sensor of a plurality of image sensors (e.g., including image sensor 130) with a zoom corresponding to the zoom setting. For example, image processing system 100 can include a wide angle image sensor with a relatively low zoom and a telephoto image sensor with a greater zoom. In some cases, based on the selected zoom setting, the zoom control mechanism 125C can capture images from a corresponding sensor.

The image sensor 130 includes one or more arrays of photodiodes or other photosensitive elements. Each photodiode measures an amount of light that eventually corresponds to a particular pixel in the image produced by the image sensor 130. In some cases, different photodiodes may be covered by different filters. In some cases, different photodiodes can be covered in color filters, and the photodiodes may measure light matching the color of the filter covering the photodiode. Various color filter arrays can be used, including a Bayer color filter array, a quad color filter array (also referred to as a quad Bayer color filter array or QCFA), and/or any other color filter array. For instance, Bayer color filters include red color filters, blue color filters, and green color filters, with each pixel of the image generated based on red light data from at least one photodiode covered in a red color filter, blue light data from at least one photodiode covered in a blue color filter, and green light data from at least one photodiode covered in a green color filter.

Returning to FIG. 1, other types of color filters may use yellow, magenta, and/or cyan (also referred to as “emerald”) color filters instead of or in addition to red, blue, and/or green color filters. In some cases, some photodiodes may be configured to measure infrared (IR) light. In some implementations, photodiodes measuring IR light may not be covered by any filter, thus allowing IR photodiodes to measure both visible (e.g., color) and IR light. In some examples, IR photodiodes may be covered by an IR filter, allowing IR light to pass through and blocking light from other parts of the frequency spectrum (e.g., visible light, color). Some image sensors (e.g., image sensor 130) may lack filters (e.g., color, IR, or any other part of the light spectrum) altogether and may instead use different photodiodes throughout the pixel array (in some cases vertically stacked). The different photodiodes throughout the pixel array can have different spectral sensitivity curves, therefore responding to different wavelengths of light. Monochrome image sensors may also lack filters and therefore lack color depth.

In some cases, the image sensor 130 may alternately or additionally include opaque and/or reflective masks that block light from reaching certain photodiodes, or portions of certain photodiodes, at certain times and/or from certain angles. In some cases, opaque and/or reflective masks may be used for phase detection autofocus (PDAF). In some cases, the opaque and/or reflective masks may be used to block portions of the electromagnetic spectrum from reaching the photodiodes of the image sensor (e.g., an IR cut filter, a UV cut filter, a band-pass filter, low-pass filter, high-pass filter, or the like). The image sensor 130 may also include an analog gain amplifier to amplify the analog signals output by the photodiodes and/or an analog to digital converter (ADC) to convert the analog signals output of the photodiodes (and/or amplified by the analog gain amplifier) into digital signals. In some cases, certain components or functions discussed with respect to one or more of the control mechanisms 120 may be included instead or additionally in the image sensor 130. The image sensor 130 may be a charge-coupled device (CCD) sensor, an electron-multiplying CCD (EMCCD) sensor, an active-pixel sensor (APS), a complimentary metal-oxide semiconductor (CMOS), an N-type metal-oxide semiconductor (NMOS), a hybrid CCD/CMOS sensor (e.g., sCMOS), or some other combination thereof.

The image processor 150 may include one or more processors, such as one or more image signal processors (ISPs) (including ISP 154), one or more host processors (including host processor 152), and/or one or more of any other type of processor 1410 discussed with respect to the computing system 1400 of FIG. 14. The host processor 152 can be a digital signal processor (DSP) and/or other type of processor. In some implementations, the image processor 150 is a single integrated circuit or chip (e.g., referred to as a system-on-chip or SoC) that includes the host processor 152 and the ISP 154. In some cases, the chip can also include one or more input/output ports (e.g., input/output (I/O) ports 156), central processing units (CPUs), graphics processing units (GPUs), broadband modems (e.g., 3G, 4G or LTE, 5G, etc.), memory, connectivity components (e.g., Bluetooth™, Global Positioning System (GPS), etc.), any combination thereof, and/or other components. The I/O ports 156 can include any suitable input/output ports or interface according to one or more protocol or specification, such as an Inter-Integrated Circuit 2 (I2C) interface, an Inter-Integrated Circuit 3 (I3C) interface, a Serial Peripheral Interface (SPI) interface, a serial General Purpose Input/Output (GPIO) interface, a Mobile Industry Processor Interface (MIPI) (such as a MIPI CSI-2 physical (PHY) layer port or interface, an Advanced High-performance Bus (AHB) bus, any combination thereof, and/or other input/output port. In one illustrative example, the host processor 152 can communicate with the image sensor 130 using an I2C port, and the ISP 154 can communicate with the image sensor 130 using an MIPI port.

The image processor 150 may perform a number of tasks, such as de-mosaicing, color space conversion, image frame downsampling, pixel interpolation, automatic exposure (AE) control, automatic gain control (AGC), CDAF, PDAF, automatic white balance, merging of image frames to form an HDR image, image recognition, object recognition, feature recognition, receipt of inputs, managing outputs, managing memory, or some combination thereof. The image processor 150 may store image frames and/or processed images in random access memory (RAM) 140/1125, read-only memory (ROM) 145/1120, a cache, a memory unit, another storage device, or some combination thereof.

Various input/output (I/O) devices 160 may be connected to the image processor 150. The I/O devices 160 can include a display screen, a keyboard, a keypad, a touchscreen, a trackpad, a touch-sensitive surface, a printer, any other output devices, any other input devices, or some combination thereof. In some cases, a caption may be input into the image processing device 105B through a physical keyboard or keypad of the I/O devices 160, or through a virtual keyboard or keypad of a touchscreen of the I/O devices 160. The I/O devices 160 may include one or more ports, jacks, or other connectors that enable a wired connection between the image capture and processing system 100 and one or more peripheral devices, over which the image capture and processing system 100 may receive data from the one or more peripheral device and/or transmit data to the one or more peripheral devices. The I/O devices 160 may include one or more wireless transceivers that enable a wireless connection between the image capture and processing system 100 and one or more peripheral devices, over which the image capture and processing system 100 may receive data from the one or more peripheral device and/or transmit data to the one or more peripheral devices. The peripheral devices may include any of the previously discussed types of I/O devices 160 and may themselves be considered I/O devices 160 once they are coupled to the ports, jacks, wireless transceivers, or other wired and/or wireless connectors.

In some cases, the image capture and processing system 100 may be a single device. In some cases, the image capture and processing system 100 may be two or more separate devices, including an image capture device 105A (e.g., a camera) and an image processing device 105B (e.g., a computing device coupled to the camera). In some implementations, the image capture device 105A and the image processing device 105B may be coupled together, for example via one or more wires, cables, or other electrical connectors, and/or wirelessly via one or more wireless transceivers. In some implementations, the image capture device 105A and the image processing device 105B may be disconnected from one another.

As shown in FIG. 1, a vertical dashed line divides the image capture and processing system 100 of FIG. 1 into two portions that represent the image capture device 105A and the image processing device 105B, respectively. The image capture device 105A includes the lens 115, control mechanisms 120, and the image sensor 130. The image processing device 105B includes the image processor 150 (including the ISP 154 and the host processor 152), the RAM 140, the ROM 145, and the I/O devices 160. In some cases, certain components illustrated in the image capture device 105A, such as the ISP 154 and/or the host processor 152, may be included in the image capture device 105A.

The image capture and processing system 100 can include an electronic device, such as a mobile or stationary telephone handset (e.g., smartphone, cellular telephone, or the like), a desktop computer, a laptop or notebook computer, a tablet computer, a set-top box, a television, a camera, a display device, a digital media player, a video gaming console, a video streaming device, an Internet Protocol (IP) camera, or any other suitable electronic device. In some examples, the image capture and processing system 100 can include one or more wireless transceivers for wireless communications, such as cellular network communications, 802.11 wi-fi communications, wireless local area network (WLAN) communications, or some combination thereof. In some implementations, the image capture device 105A and the image processing device 105B can be different devices. For instance, the image capture device 105A can include a camera device and the image processing device 105B can include a computing device, such as a mobile handset, a desktop computer, or other computing device.

While the image capture and processing system 100 is shown to include certain components, one of ordinary skill will appreciate that the image capture and processing system 100 can include more components than those shown in FIG. 1. The components of the image capture and processing system 100 can include software, hardware, or one or more combinations of software and hardware. For example, in some implementations, the components of the image capture and processing system 100 can include and/or can be implemented using electronic circuits or other electronic hardware, which can include one or more programmable electronic circuits (e.g., microprocessors, GPUs, DSPs, CPUs, and/or other suitable electronic circuits), and/or can include and/or be implemented using computer software, firmware, or any combination thereof, to perform the various operations described herein. The software and/or firmware can include one or more instructions stored on a computer-readable storage medium and executable by one or more processors of the electronic device implementing the image capture and processing system 100.

In some examples, the extended reality (XR) system 200 of FIG. 2 can include the image capture and processing system 100, the image capture device 105A, the image processing device 105B, or a combination thereof.

FIG. 2 is a diagram illustrating an architecture of an example extended reality (XR) system 200, in accordance with some aspects of the disclosure. The XR system 200 can run (or execute) XR applications and implement XR operations. In some examples, the XR system 200 can perform tracking and localization, mapping of an environment in the physical world (e.g., a scene), and/or positioning and rendering of virtual content on a display 209 (e.g., a screen, visible plane/region, and/or other display) as part of an XR experience. For example, the XR system 200 can generate a map (e.g., a three-dimensional (3D) map) of an environment in the physical world, track a pose (e.g., location and position) of the XR system 200 relative to the environment (e.g., relative to the 3D map of the environment), position and/or anchor virtual content in a specific location(s) on the map of the environment, and render the virtual content on the display 209 such that the virtual content appears to be at a location in the environment corresponding to the specific location on the map of the scene where the virtual content is positioned and/or anchored. The display 209 can include a glass, a screen, a lens, a projector, and/or other display mechanism that allows a user to see the real-world environment and also allows XR content to be overlaid, overlapped, blended with, or otherwise displayed thereon.

In this illustrative example, the XR system 200 includes one or more image sensors 202, an accelerometer 204, a gyroscope 206, storage 207, compute components 210, an XR engine 220, an image processing engine 224, a rendering engine 226, and a communications engine 228. It should be noted that the components 202-228 shown in FIG. 2 are non-limiting examples provided for illustrative and explanation purposes, and other examples can include more, fewer, or different components than those shown in FIG. 2. For example, in some cases, the XR system 200 can include one or more other sensors (e.g., one or more inertial measurement units (IMUs), radars, light detection and ranging (LIDAR) sensors, radio detection and ranging (RADAR) sensors, sound detection and ranging (SODAR) sensors, sound navigation and ranging (SONAR) sensors. audio sensors, etc.), one or more display devices, one more other processing engines, one or more other hardware components, and/or one or more other software and/or hardware components that are not shown in FIG. 2. While various components of the XR system 200, such as the image sensor 202, may be referenced in the singular form herein, it should be understood that the XR system 200 may include multiple of any component discussed herein (e.g., multiple image sensors 202).

The XR system 200 includes or is in communication with (wired or wirelessly) an input device 208. The input device 208 can include any suitable input device, such as a touchscreen, a pen or other pointer device, a keyboard, a mouse a button or key, a microphone for receiving voice commands, a gesture input device for receiving gesture commands, a video game controller, a steering wheel, a joystick, a set of buttons, a trackball, a remote control, any other input device 1145 discussed herein, or any combination thereof. In some cases, the image sensor 202 can capture images that can be processed for interpreting gesture commands.

The XR system 200 can also communicate with one or more other electronic devices (wired or wirelessly). For example, communications engine 228 can be configured to manage connections and communicate with one or more electronic devices. In some cases, the communications engine 228 can correspond to the communications interface 1140 of FIG. 11.

In some implementations, the one or more image sensors 202, the accelerometer 204, the gyroscope 206, storage 207, compute components 210, XR engine 220, image processing engine 224, and rendering engine 226 can be part of the same computing device. For example, in some cases, the one or more image sensors 202, the accelerometer 204, the gyroscope 206, storage 207, compute components 210, XR engine 220, image processing engine 224, and rendering engine 226 can be integrated into an HMD, extended reality glasses, smartphone, laptop, tablet computer, gaming system, and/or any other computing device.

However, in some implementations, the one or more image sensors 202, the accelerometer 204, the gyroscope 206, storage 207, compute components 210, XR engine 220, image processing engine 224, and rendering engine 226 can be part of two or more separate computing devices. For example, in some cases, some of the components 202-226 can be part of, or implemented by, one computing device and the remaining components can be part of, or implemented by, one or more other computing devices.

The storage 207 can be any storage device(s) for storing data. Moreover, the storage 207 can store data from any of the components of the XR system 200. For example, the storage 207 can store data from the image sensor 202 (e.g., image or video data), data from the accelerometer 204 (e.g., measurements), data from the gyroscope 206 (e.g., measurements), data from the compute components 210 (e.g., processing parameters, preferences, virtual content, rendering content, scene maps, tracking and localization data, object detection data, privacy data, XR application data, face recognition data, occlusion data, etc.), data from the XR engine 220, data from the image processing engine 224, and/or data from the rendering engine 226 (e.g., output frames). In some examples, the storage 207 can include a buffer for storing frames for processing by the compute components 210.

The one or more compute components 210 can include a central processing unit (CPU) 212, a graphics processing unit (GPU) 214, a digital signal processor (DSP) 216, an image signal processor (ISP) 218, and/or other processor (e.g., a neural processing unit (NPU) implementing one or more trained neural networks). The compute components 210 can perform various operations such as image enhancement, computer vision, graphics rendering, extended reality operations (e.g., tracking, localization, pose estimation, mapping, content anchoring, content rendering, etc.), image and/or video processing, sensor processing, recognition (e.g., text recognition, facial recognition, object recognition, feature recognition, tracking or pattern recognition, scene recognition, occlusion detection, etc.), trained machine learning operations, filtering, and/or any of the various operations described herein. In some examples, the compute components 210 can implement (e.g., control, operate, etc.) the XR engine 220, the image processing engine 224, and the rendering engine 226. In other examples, the compute components 210 can also implement one or more other processing engines.

The image sensor 202 can include any image and/or video sensors or capturing devices. In some examples, the image sensor 202 can be part of a multiple-camera assembly, such as a dual-camera assembly. The image sensor 202 can capture image and/or video content (e.g., raw image and/or video data), which can then be processed by the compute components 210, the XR engine 220, the image processing engine 224, and/or the rendering engine 226 as described herein. In some examples, the image sensors 202 may include an image capture and processing system 100, an image capture device 105A, an image processing device 105B, or a combination thereof.

In some examples, the image sensor 202 can capture image data and can generate images (also referred to as frames) based on the image data and/or can provide the image data or frames to the XR engine 220, the image processing engine 224, and/or the rendering engine 226 for processing. An image or frame can include a video frame of a video sequence or a still image. An image or frame can include a pixel array representing a scene. For example, an image can be a red-green-blue (RGB) image having red, green, and blue color components per pixel; a luma, chroma-red, chroma-blue (YCbCr) image having a luma component and two chroma (color) components (chroma-red and chroma-blue) per pixel; or any other suitable type of color or monochrome image.

In some cases, the image sensor 202 (and/or other camera of the XR system 200) can be configured to also capture depth information. For example, in some implementations, the image sensor 202 (and/or other camera) can include an RGB-depth (RGB-D) camera. In some cases, the XR system 200 can include one or more depth sensors (not shown) that are separate from the image sensor 202 (and/or other camera) and that can capture depth information. For instance, such a depth sensor can obtain depth information independently from the image sensor 202. In some examples, a depth sensor can be physically installed in the same general location as the image sensor 202, but may operate at a different frequency or frame rate from the image sensor 202. In some examples, a depth sensor can take the form of a light source that can project a structured or textured light pattern, which may include one or more narrow bands of light, onto one or more objects in a scene. Depth information can then be obtained by exploiting geometrical distortions of the projected pattern caused by the surface shape of the object. In one example, depth information may be obtained from stereo sensors such as a combination of an infra-red structured light projector and an infra-red camera registered to a camera (e.g., an RGB camera).

The XR system 200 can also include other sensors in its one or more sensors. The one or more sensors can include one or more accelerometers (e.g., accelerometer 204), one or more gyroscopes (e.g., gyroscope 206), and/or other sensors. The one or more sensors can provide velocity, orientation, and/or other position-related information to the compute components 210. For example, the accelerometer 204 can detect acceleration by the XR system 200 and can generate acceleration measurements based on the detected acceleration. In some cases, the accelerometer 204 can provide one or more translational vectors (e.g., up/down, left/right, forward/back) that can be used for determining a position or pose of the XR system 200. The gyroscope 206 can detect and measure the orientation and angular velocity of the XR system 200. For example, the gyroscope 206 can be used to measure the pitch, roll, and yaw of the XR system 200. In some cases, the gyroscope 206 can provide one or more rotational vectors (e.g., pitch, yaw, roll). In some examples, the image sensor 202 and/or the XR engine 220 can use measurements obtained by the accelerometer 204 (e.g., one or more translational vectors) and/or the gyroscope 206 (e.g., one or more rotational vectors) to calculate the pose of the XR system 200. As previously noted, in other examples, the XR system 200 can also include other sensors, such as an inertial measurement unit (IMU), a magnetometer, a gaze and/or eye tracking sensor, a machine vision sensor, a smart scene sensor, a speech recognition sensor, an impact sensor, a shock sensor, a position sensor, a tilt sensor, etc.

As noted above, in some cases, the one or more sensors can include at least one IMU. An IMU is an electronic device that measures the specific force, angular rate, and/or the orientation of the XR system 200, using a combination of one or more accelerometers, one or more gyroscopes, and/or one or more magnetometers. In some examples, the one or more sensors can output measured information associated with the capture of an image captured by the image sensor 202 (and/or other camera of the XR system 200) and/or depth information obtained using one or more depth sensors of the XR system 200.

The output of one or more sensors (e.g., the accelerometer 204, the gyroscope 206, one or more IMUs, and/or other sensors) can be used by the XR engine 220 to determine a pose of the XR system 200 (also referred to as the head pose) and/or the pose of the image sensor 202 (or other camera of the XR system 200). In some cases, the pose of the XR system 200 and the pose of the image sensor 202 (or other camera) can be the same. The pose of image sensor 202 refers to the position and orientation of the image sensor 202 relative to a frame of reference (e.g., with respect to the scene 110). In some implementations, the camera pose can be determined for 6-Degrees of Freedom (6DoF), which refers to three translational components (e.g., which can be given by X (horizontal), Y (vertical), and Z (depth) coordinates relative to a frame of reference, such as the image plane) and three angular components (e.g. roll, pitch, and yaw relative to the same frame of reference). In some implementations, the camera pose can be determined for 3-Degrees of Freedom (3DoF), which refers to the three angular components (e.g. roll, pitch, and yaw).

In some cases, a device tracker (not shown) can use the measurements from the one or more sensors and image data from the image sensor 202 to track a pose (e.g., a 6DoF pose) of the XR system 200. For example, the device tracker can fuse visual data (e.g., using a visual tracking solution) from the image data with inertial data from the measurements to determine a position and motion of the XR system 200 relative to the physical world (e.g., the scene) and a map of the physical world. As described below, in some examples, when tracking the pose of the XR system 200, the device tracker can generate a three-dimensional (3D) map of the scene (e.g., the real world) and/or generate updates for a 3D map of the scene. The 3D map updates can include, for example and without limitation, new or updated features and/or feature or landmark points associated with the scene and/or the 3D map of the scene, localization updates identifying or updating a position of the XR system 200 within the scene and the 3D map of the scene, etc. The 3D map can provide a digital representation of a scene in the real/physical world. In some examples, the 3D map can anchor location-based objects and/or content to real-world coordinates and/or objects. The XR system 200 can use a mapped scene (e.g., a scene in the physical world represented by, and/or associated with, a 3D map) to merge the physical and virtual worlds and/or merge virtual content or objects with the physical environment.

In some aspects, the pose of image sensor 202 and/or the XR system 200 as a whole can be determined and/or tracked by the compute components 210 using a visual tracking solution based on images captured by the image sensor 202 (and/or other camera of the XR system 200). For instance, in some examples, the compute components 210 can perform tracking using computer vision-based tracking, model-based tracking, and/or simultaneous localization and mapping (SLAM) techniques. For instance, the compute components 210 can perform SLAM or can be in communication (wired or wireless) with a SLAM system (not shown). SLAM refers to a class of techniques where a map of an environment (e.g., a map of an environment being modeled by XR system 200) is created while simultaneously tracking the pose of a camera (e.g., image sensor 202) and/or the XR system 200 relative to that map. The map can be referred to as a SLAM map, and can be three-dimensional (3D). The SLAM techniques can be performed using color or grayscale image data captured by the image sensor 202 (and/or other camera of the XR system 200), and can be used to generate estimates of 6DoF pose measurements of the image sensor 202 and/or the XR system 200. Such a SLAM technique configured to perform 6DoF tracking can be referred to as 6DoF SLAM. In some cases, the output of the one or more sensors (e.g., the accelerometer 204, the gyroscope 206, one or more IMUs, and/or other sensors) can be used to estimate, correct, and/or otherwise adjust the estimated pose.

In some cases, the 6DoF SLAM (e.g., 6DoF tracking) can associate features observed from certain input images from the image sensor 202 (and/or other camera) to the SLAM map. For example, 6DoF SLAM can use feature point associations from an input image to determine the pose (position and orientation) of the image sensor 202 and/or XR system 200 for the input image. 6DoF mapping can also be performed to update the SLAM map. In some cases, the SLAM map maintained using the 6DoF SLAM can contain 3D feature points triangulated from two or more images. For example, key frames can be selected from input images or a video stream to represent an observed scene. For every key frame, a respective 6DoF camera pose associated with the image can be determined. The pose of the image sensor 202 and/or the XR system 200 can be determined by projecting features from the 3D SLAM map into an image or video frame and updating the camera pose from verified 2D-3D correspondences.

In one illustrative example, the compute components 210 can extract feature points from certain input images (e.g., every input image, a subset of the input images, etc.) or from each key frame. A feature point (also referred to as a registration point) as used herein is a distinctive or identifiable part of an image, such as a part of a hand, an edge of a table, among others. Features extracted from a captured image can represent distinct feature points along three-dimensional space (e.g., coordinates on X, Y, and Z-axes), and every feature point can have an associated feature location. The feature points in key frames either match (are the same or correspond to) or fail to match the feature points of previously captured input images or key frames. Feature detection can be used to detect the feature points. Feature detection can include an image processing operation used to examine one or more pixels of an image to determine whether a feature exists at a particular pixel. Feature detection can be used to process an entire captured image or certain portions of an image. For each image or key frame, once features have been detected, a local image patch around the feature can be extracted. Features may be extracted using any suitable technique, such as Scale Invariant Feature Transform (SIFT) (which localizes features and generates their descriptions), Learned Invariant Feature Transform (LIFT), Speed Up Robust Features (SURF), Gradient Location-Orientation histogram (GLOH), Oriented Fast and Rotated Brief (ORB), Binary Robust Invariant Scalable Keypoints (BRISK), Fast Retina Keypoint (FREAK), KAZE, Accelerated KAZE (AKAZE), Normalized Cross Correlation (NCC), descriptor matching, another suitable technique, or a combination thereof.

As one illustrative example, the compute components 210 can extract feature points corresponding to a mobile device (e.g., mobile device 440 of FIG. 4, mobile device 540 of FIG. 5), or the like. In some cases, feature points corresponding to the mobile device can be tracked to determine a pose of the mobile device. As described in more detail below, the pose of the mobile device can be used to determine a location for projection of AR media content that can enhance media content displayed on a display of the mobile device.

In some cases, the XR system 200 can also track the hand and/or fingers of the user to allow the user to interact with and/or control virtual content in a virtual environment. For example, the XR system 200 can track a pose and/or movement of the hand and/or fingertips of the user to identify or translate user interactions with the virtual environment. The user interactions can include, for example and without limitation, moving an item of virtual content, resizing the item of virtual content, selecting an input interface element in a virtual user interface (e.g., a virtual representation of a mobile phone, a virtual keyboard, and/or other virtual interface), providing an input through a virtual user interface, etc.

A neural network is an example of a machine learning system, and a neural network can include an input layer, one or more hidden layers, and an output layer. Data is provided from input nodes of the input layer, processing is performed by hidden nodes of the one or more hidden layers, and an output is produced through output nodes of the output layer. Deep learning networks typically include multiple hidden layers. Each layer of the neural network can include feature maps or activation maps that can include artificial neurons (or nodes). A feature map can include a filter, a kernel, or the like. The nodes can include one or more weights used to indicate an importance of the nodes of one or more of the layers. In some cases, a deep learning network can have a series of many hidden layers, with early layers being used to determine simple and low level characteristics of an input, and later layers building up a hierarchy of more complex and abstract characteristics.

A deep learning architecture may learn a hierarchy of features. If presented with visual data, for example, the first layer may learn to recognize relatively simple features, such as edges, in the input stream. In another example, if presented with auditory data, the first layer may learn to recognize spectral power in specific frequencies. The second layer, taking the output of the first layer as input, may learn to recognize combinations of features, such as simple shapes for visual data or combinations of sounds for auditory data. For instance, higher layers may learn to represent complex shapes in visual data or words in auditory data. Still higher layers may learn to recognize common visual objects or spoken phrases.

Deep learning architectures may perform especially well when applied to problems that have a natural hierarchical structure. For example, the classification of motorized vehicles may benefit from first learning to recognize wheels, windshields, and other features. These features may be combined at higher layers in different ways to recognize cars, trucks, and airplanes.

Neural networks may be designed with a variety of connectivity patterns. In feed-forward networks, information is passed from lower to higher layers, with each neuron in a given layer communicating to neurons in higher layers. A hierarchical representation may be built up in successive layers of a feed-forward network, as described above. Neural networks may also have recurrent or feedback (also called top-down) connections. In a recurrent connection, the output from a neuron in a given layer may be communicated to another neuron in the same layer. A recurrent architecture may be helpful in recognizing patterns that span more than one of the input data chunks that are delivered to the neural network in a sequence. A connection from a neuron in a given layer to a neuron in a lower layer is called a feedback (or top-down) connection. A network with many feedback connections may be helpful when the recognition of a high-level concept may aid in discriminating the particular low-level features of an input. The connections between layers of a neural network may be fully connected or locally connected. Various examples of neural network architectures are described below with respect to FIG. 3A-FIG. 4.

Neural networks may be designed with a variety of connectivity patterns. In feed-forward networks, information is passed from lower to higher layers, with each neuron in a given layer communicating to neurons in higher layers. A hierarchical representation may be built up in successive layers of a feed-forward network, as described above. Neural networks may also have recurrent or feedback (also called top-down) connections. In a recurrent connection, the output from a neuron in a given layer may be communicated to another neuron in the same layer. A recurrent architecture may be helpful in recognizing patterns that span more than one of the input data chunks that are delivered to the neural network in a sequence. A connection from a neuron in a given layer to a neuron in a lower layer is called a feedback (or top-down) connection. A network with many feedback connections may be helpful when the recognition of a high-level concept may aid in discriminating the particular low-level features of an input.

The connections between layers of a neural network may be fully connected or locally connected. FIG. 3A illustrates an example of a fully connected neural network 302. In a fully connected neural network 302, a neuron in a first layer may communicate its output to every neuron in a second layer, so that each neuron in the second layer will receive input from every neuron in the first layer. FIG. 3B illustrates an example of a locally connected neural network 304. In a locally connected neural network 304, a neuron in a first layer may be connected to a limited number of neurons in the second layer. More generally, a locally connected layer of the locally connected neural network 304 may be configured so that each neuron in a layer will have the same or a similar connectivity pattern, but with connections strengths that may have different values (e.g., 310, 312, 314, and 316). The locally connected connectivity pattern may give rise to spatially distinct receptive fields in a higher layer, because the higher layer neurons in a given region may receive inputs that are tuned through training to the properties of a restricted portion of the total input to the network.

One example of a locally connected neural network is a convolutional neural network. FIG. 3C illustrates an example of a convolutional neural network 306. The convolutional neural network 306 may be configured such that the connection strengths associated with the inputs for each neuron in the second layer are shared (e.g., 308). Convolutional neural networks may be well suited to problems in which the spatial location of inputs is meaningful. Convolutional neural network 306 may be used to perform one or more aspects of video compression and/or decompression, according to aspects of the present disclosure.

One type of convolutional neural network is a deep convolutional network (DCN). FIG. 3D illustrates a detailed example of a DCN 300 designed to recognize visual features from an image 326 input from an image capturing device 330, such as a car-mounted camera. The DCN 300 of the current example may be trained to identify traffic signs and a number provided on the traffic sign. Of course, the DCN 300 may be trained for other tasks, such as identifying lane markings, identifying traffic lights, detecting people and/or objects, etc.

The DCN 300 may be trained with supervised learning. During training, the DCN 300 may be presented with an image, such as the image 326 of a speed limit sign, and a forward pass may then be computed to produce an output 322. The DCN 300 may include a feature extraction section and a classification section. Upon receiving the image 326, a convolutional layer 332 may apply convolutional kernels (not shown) to the image 326 to generate a first set of feature maps 318. As an example, the convolutional kernel for the convolutional layer 332 may be a 5×5 kernel that generates 28×28 feature maps. In the present example, because four different feature maps are generated in the first set of feature maps 318, four different convolutional kernels were applied to the image 326 at the convolutional layer 332. The convolutional kernels may also be referred to as filters or convolutional filters.

The first set of feature maps 318 may be subsampled by a max pooling layer (not shown) to generate a second set of feature maps 320. The max pooling layer reduces the size of the first set of feature maps 318. That is, a size of the second set of feature maps 320, such as 14×14, is less than the size of the first set of feature maps 318, such as 28×28. The reduced size provides similar information to a subsequent layer while reducing memory consumption. The second set of feature maps 320 may be further convolved via one or more subsequent convolutional layers (not shown) to generate one or more subsequent sets of feature maps (not shown).

In the example of FIG. 3D, the second set of feature maps 320 is convolved to generate a first feature vector 324. Furthermore, the first feature vector 324 is further convolved to generate a second feature vector 328. Each feature of the second feature vector 328 may include a number that corresponds to a possible feature of the image 326, such as “sign,” “60,” and “100.” A softmax function (not shown) may convert the numbers in the second feature vector 328 to a probability. As such, an output 322 of the DCN 300 is a probability of the image 326 including one or more features.

In the present example, the probabilities in the output 322 for “sign” and “60” are higher than the probabilities of the others of the output 322, such as “30,” “40,” “50,” “70,” “80,” “90,” and “100”. Before training, the output 322 produced by the DCN 300 is likely to be incorrect. Thus, an error may be calculated between the output 322 and a target output. The target output is the ground truth of the image 326 (e.g., “sign” and “60”). The weights of the DCN 300 may then be adjusted so the output 322 of the DCN 300 is more closely aligned with the target output.

To adjust the weights, a learning algorithm may compute a gradient vector for the weights. The gradient may indicate an amount that an error would increase or decrease if the weight were adjusted. At the top layer, the gradient may correspond directly to the value of a weight connecting an activated neuron in the penultimate layer and a neuron in the output layer. In lower layers, the gradient may depend on the value of the weights and on the computed error gradients of the higher layers. The weights may then be adjusted to reduce the error. This manner of adjusting the weights may be referred to as “back propagation” as it involves a “backward pass” through the neural network.

In practice, the error gradient of weights may be calculated over a small number of examples, so that the calculated gradient approximates the true error gradient. This approximation method may be referred to as stochastic gradient descent. Stochastic gradient descent may be repeated until the achievable error rate of the entire system has stopped decreasing or until the error rate has reached a target level. After learning, the DCN may be presented with new images and a forward pass through the network may yield an output 322 that may be considered an inference or a prediction of the DCN.

Deep belief networks (DBNs) are probabilistic models comprising multiple layers of hidden nodes. DBNs may be used to extract a hierarchical representation of training data sets. A DBN may be obtained by stacking up layers of Restricted Boltzmann Machines (RBMs). An RBM is a type of artificial neural network that can learn a probability distribution over a set of inputs. Because RBMs can learn a probability distribution in the absence of information about the class to which each input should be categorized, RBMs are often used in unsupervised learning. Using a hybrid unsupervised and supervised paradigm, the bottom RBMs of a DBN may be trained in an unsupervised manner and may serve as feature extractors, and the top RBM may be trained in a supervised manner (on a joint distribution of inputs from the previous layer and target classes) and may serve as a classifier.

Deep convolutional networks (DCNs) are networks of convolutional networks, configured with additional pooling and normalization layers. DCNs have achieved state-of-the-art performance on many tasks. DCNs can be trained using supervised learning in which both the input and output targets are known for many exemplars and are used to modify the weights of the network by use of gradient descent methods.

DCNs may be feed-forward networks. In addition, as described above, the connections from a neuron in a first layer of a DCN to a group of neurons in the next higher layer are shared across the neurons in the first layer. The feed-forward and shared connections of DCNs may be exploited for fast processing. The computational burden of a DCN may be much less, for example, than that of a similarly sized neural network that comprises recurrent or feedback connections.

The processing of each layer of a convolutional network may be considered a spatially invariant template or basis projection. If the input is first decomposed into multiple channels, such as the red, green, and blue channels of a color image, then the convolutional network trained on that input may be considered three-dimensional, with two spatial dimensions along the axes of the image and a third dimension capturing color information. The outputs of the convolutional connections may be considered to form a feature map in the subsequent layer, with each element of the feature map (e.g., feature maps 320) receiving input from a range of neurons in the previous layer (e.g., feature maps 318) and from each of the multiple channels. The values in the feature map may be further processed with a non-linearity, such as a rectification, max(0,x). Values from adjacent neurons may be further pooled, which corresponds to down sampling, and may provide additional local invariance and dimensionality reduction.

FIG. 4 is a block diagram illustrating an example of a deep convolutional network 450. The deep convolutional network 450 may include multiple different types of layers based on connectivity and weight sharing. As shown in FIG. 4, the deep convolutional network 450 includes the convolution blocks 454A, 454B. Each of the convolution blocks 454A, 454B may be configured with a convolution layer (CONV) 456, a normalization layer (LNorm) 458, and a max pooling layer (MAX POOL) 460.

The convolution layers 456 may include one or more convolutional filters, which may be applied to the input data 452 to generate a feature map. Although only two convolution blocks 454A, 454B are shown, the present disclosure is not so limiting, and instead, any number of convolution blocks (e.g., convolution blocks 454A, 454B) may be included in the deep convolutional network 450 according to design preference. The normalization layer 458 may normalize the output of the convolution filters. For example, the normalization layer 458 may provide whitening or lateral inhibition. The max pooling layer 460 may provide down sampling aggregation over space for local invariance and dimensionality reduction.

The parallel filter banks, for example, of a deep convolutional network may be loaded on a CPU 212 or GPU 214 of the compute components 210 to achieve high performance and low power consumption. In alternative aspects, the parallel filter banks may be loaded on the DSP 216 or an ISP 218 of the compute components 210. In addition, the deep convolutional network 450 may access other processing blocks that may be present on the compute components 210, such as sensor processor and navigation module, dedicated, respectively, to sensors and navigation.

The deep convolutional network 450 may also include one or more fully connected layers, such as layer 462A (labeled “FC1”) and layer 462B (labeled “FC2”). The deep convolutional network 450 may further include a logistic regression (LR) layer 464. Between each layer 456, 458, 460, 462A, 462B, 464 of the deep convolutional network 450 are weights (not shown) that are to be updated. The output of each of the layers (e.g., 456, 458, 460, 462A, 462B, 464) may serve as an input of a succeeding one of the layers (e.g., 456, 458, 460, 462A, 462B, 464) in the deep convolutional network 450 to learn hierarchical feature representations from input data 452 (e.g., images, audio, video, sensor data and/or other input data) supplied at the first of the convolution blocks 454A. The output of the deep convolutional network 450 is a classification score 466 for the input data 452. The classification score 466 may be a set of probabilities, where each probability is the probability of the input data including a feature from a set of features.

FIG. 5 illustrates an XR system 500 including companion devices, in accordance with aspects of the present disclosure. In this example, XR system 500 may include a relatively lightweight HMD 502. In some cases, the HMD 502 may be a relatively lightweight HMD 502, as compared to more fully featured HMDs. For example, HMD 502 may be an AR headset that may include a pair of eye tracking cameras 504 and optionally an audio sensor (e.g., microphone, microphone array, etc., not shown) along with sensors for determining a head pose. The HMD 502 may lack certain sensors, such as additional cameras like a mouth camera, body tracking cameras, pose tracking cameras, and the like, that may be found in more fully featured HMDs. The HMD 502 may communicate with a companion device 506 that is separate from the HMD 502. The HMD 502 may communicate with the companion device 506 via any wired or wireless communications technique. In some cases, the companion device 506 may be a mobile device, such as a smartphone. The companion device 506 may include one or more cameras 508. The companion device 506 may be positioned such that the HMD 502 and/or user of HMD 502 are within a field of view of the one or more cameras 508 of the companion device 506. By allowing the companion device 506 to capture images of the HMD 502 and/or user of HMD 502, the companion device 506 may be used as an additional imaging sensor for tracking the user of the HMD 502. In some cases, images from the companion device 506 may be used to provide information about a mouth, body, and portions of the face of the user of the HMD 502. The information from the companion device 506 may be combined with information from the eye tracking cameras 504 to generate an avatar, for example, that may be used in telepresence applications for the user of the HMD 502, companion device 506, etc. In some cases, an audio sensor of the companion device 506 may also be used to capture audio information. In some cases, the audio sensor of the companion device 506 may be used in conjunction with an audio sensor of the HMD 502, instead of the audio sensor of the HMD 502, or in place of an audio sensor on the HMD 502 (e.g., where the HMD 502 lacks an audio sensor). In some cases, a XR system, such as XR system 500, including a HMD 502 and a companion device 506 (and optionally an audio sensor) may be referred to as a first telepresence topology.

In some cases, it may be difficult to obtain full body images of a user of the HMD 502 with just the one or more cameras 508 of the companion device 506. For example, the companion device 506 may be placed on an elevated surface, such as a desk, and/or tilted backwards (e.g., in a stand on the desk) and a lower portion of the user of the HMD 502 may not be in the field of view of the companion device 506. In some cases, portions of the user of the HMD 502 which are not within a field of view of the companion device 506 may not be rendered as a part of a corresponding avatar representing the user of the HMD 502, or those corresponding portions of the avatar may not be animated/updated. In some cases, a region of an environment (e.g., a room, office, corner, etc. of a house, business, etc.) may be configured as a telepresence station including one or more additional sensors, such as telepresence cameras 510, telepresence audio sensor 512, and the like). The additional sensors may provide additional information to the HMD 502 and/or companion device 506 that may be used to generate an avatar for the user of the companion device 506. In some cases, a XR system, such as XR system 500, including the HMD 502, the companion device 506, and one or more telepresence cameras 510 may be referred to as a second telepresence topology.

As the HMD 502 is separate from the companion device 506 and/or the additional sensors, a timing of the HMD 502, companion device 506 and/or additional sensors may be synchronized to help generate the avatar. Additionally, as the one or more cameras 508 and/or telepresence cameras 510 may not be rigidly mounted in a fixed position with respect to each other and this potentially differing locations, along with possible differences in lighting, occlusion by the HMD 502, and pose variations (e.g., of the user with respect to the cameras), may be accounted for when generating the avatar.

In some cases, tracking algorithms, such as face and/or body tracking algorithms for generating and/or animating avatars may benefit from time synchronized images from multiple cameras where the images are captured based on a same clock (e.g., synchronized clocks) so that a middle of an exposure time for the multiple cameras (e.g., eye tracking cameras 504, and the one or more cameras 508 of the companion device 506 and optionally the telepresence cameras 510) is time aligned across the multiple cameras.

FIG. 6 is a block diagram illustrating a technique 600 for managing clock synchronization for devices for virtual telepresence, in accordance with aspects of the present disclosure. FIG. 6 includes an HMD 602 communicatively coupled to a companion device 606 operating as an XR system in the first telepresence topology. In some cases, HMD 602 may be similar to HMD 502 of FIG. 5 and companion device 606 may be similar to companion device 506 of FIG. 5. The HMD 602 may be communicatively coupled to the companion device 606, in FIG. 6, via a Wi-Fi connection. The HMD 602 may include an HMD face tracking application 608 executing on (e.g., on a processor of) the HMD 602. The HMD face tracking application 608 may work in conjunction with a companion device tracking application 610 executing on (e.g., on a processor of) the companion device 606 to track at least a face of a user of the HMD 602 and companion device 606. In some cases, the companion device tracking application 610 may communicate with the HMD face tracking application 608 via the Wi-Fi connection using a Wi-Fi application stack 612 of the companion device 606 and a Wi-Fi application stack 614 of the HMD 602. The Wi-Fi application stack 612, 614, may refer to software (e.g., applications, drivers, etc.) that provide wireless network access via a Wi-Fi device of a wireless device, such as HMD 602 or companion device 606. In some cases, the companion device 606 (or the HMD 602) may act as a software enabled access point (softAP) and the HMD 602 may act as a wireless station (STA) and connect to the companion device 606 (or vice versa).

In some cases, a Wi-Fi access point (AP), such as a softAP, may broadcast a timing synchronization function (TSF) signal 616. This TSF may be based on a 1 MHz clock with microsecond ticks. Wi-Fi signals may be transmitted at precise times and the TSF may be used to provide a network time for timing synchronization across STAs accessing a basic service set (BSS) of the AP. The network time provides a common time (e.g., clock) that multiple networked devices may use for network communications. Each STA may maintain a local TSF timer and may synchronize the local TSF timer to the TSF signal transmitted by the AP. In some cases, the Wi-Fi application stack 614 of the HMD 602 may expose (e.g., make accessible via an API or some other software interface) the local TSF timer to the HMD face tracking application 608. Similarly, the Wi-Fi application stack 612 of the companion device 606 may expose the TSF time to the companion device tracking application 610. As an example, if the

HMD face tracking application 608 (or companion device tracking application 610) is internally operating based on a system clock or other timer interface, the HMD face tracking application 608 (or companion device tracking application 610) may include a TSF interface 618 that may map a time associated with events, such as capturing an image, from the system clock or other timer interface (e.g., a first clock) to the TSF time (e.g., a second clock). Thus, a captured image may be associated with a capture time based on the TSF time.

In cases where the TSF is unavailable, such as when using wired connections between the HMD 602, companion device 606, and optionally, additional sensors, another network time synchronization protocol, such as precision time protocol, may be used in place of TSF.

For the second telepresence topology where additional sensors, such as a telepresence camera 510 of FIG. 5, are available, the additional sensors may be synchronized to the companion device 606 (or HMD 602) in a manner similar to that discussed above with respect to the HMD 602 as a STA.

In some cases, the capture time associated with a captured image may be used to align times when future images may be captured by the HMD 602 and companion device 606 (and telepresence cameras, if present). As an example, with the HMD 602 operating as a STA and synchronizing image capture timing with the companion device 606, the HMD face tracking application 608 may receive a first image from the HMD camera 620. The first image may be associated with a capture time based on a system clock. In one illustrative example, the capture time may be determined at the middle of the exposure of the first image. In other examples, the capture time can be determined at other time points within the exposure of the first image. The HMD face tracking application 608 may determine a corresponding TSF time (e.g., mapping the system clock time to the TSF time) and associate (e.g., label, tag, add metadata, timestamp, etc.) the first image with the TSF time. The first image with a TSF timestamp may then be sent to the companion device 606.

In some cases, the companion device tracking application 610 may receive the first image along with images from the companion device camera 622 and possibly images from telepresence camera(s). The companion device tracking application 610 may order the received images based on TSF timestamps and process the images for face/body tracking. The companion device tracking application 610 may also determine a phase delta between when the images were captured. For example, the companion device tracking application 610 may determine that the first image was captured n milliseconds before images were captured by the companion device camera 622 and the phase delta information may indicate an amount of time to delay (or speed up) capture of a next image to help synchronize the cameras of the companion device camera 622 and HMD camera 620. This phase delta information (e.g., based on a time difference between an image capture time of a first camera as compared to a second camera) may then be sent to the HMD 602 and the HMD face tracking application 608. Different cameras may receive different phase delta information, depending on when the initial images were captured. The phase delta information may help align a first camera capture times to capture times of a second camera, or the phase delta information may align the first camera capture time and second camera capture time with a common capture time.

The HMD face tracking application 608 may receive the phase delta for the first camera and use this phase delta information to adjust a capture time for the HMD camera 620. For example, the HMD face tracking application 608 may adjust a vertical blanking period of the HMD camera 620. The vertical blanking period may be a period of time between an end of an exposure and a start of a next exposure. In some cases, increasing the vertical blanking period may slow down when the next exposure is captured (e.g., where the phase delta is positive) and decreasing the vertical blanking period may speed up when the next exposure is captured (e.g., where the phase delta is negative). In some cases, adjusting the vertical blanking period may occur over multiple frames, for example, if the phase delta is too large to adjust for in a single vertical blanking period. A second image may be captured after the vertical blanking period is adjusted.

In some cases, the companion device tracking application 610 may also/instead adjust a capture time for the companion device camera 622 in a substantially similar way (e.g., based on a phase delta between when an image is captured by the companion device camera 622 and when another image is captured by the HMD 602). While discussed in context of the companion device tracking application 610 determining a phase delta and adjusting capture times for either the HMD 602 and/or companion device 606, it should be understood that these operations may instead be performed by the HMD face tracking application 608 executing on the HMD 602. In some cases, determining a phase delta and adjusting capture times may be performed in a loop (e.g., substantially continuously) while image data from the HMD 602 and companion device 606 (and optionally telepresence camera(s)) are used to generate the avatar for telepresence. Monitoring and adjusting capture times in a loop can help correct for potential clock drift over time after the initial synchronization of the cameras.

In some cases, as the cameras of the companion device (and possibly the telepresence cameras) may not be rigidly mounted with respect to cameras of the HMD, it may be useful to estimate a pose of the external cameras (e.g., cameras of the companion device and the telepresence cameras) based on a mesh estimation network for generating the avatars. In some cases, the mesh estimation network may include one or more machine learning algorithms may be used to estimate a head and body mesh of a user of the XR system. The head and body mesh may be geometrical representation of an object using vertices, edges, and faces of polygons to define an object (e.g., a head and body of a user of the XR system) in a virtual three-dimensional space. The head and body mesh may be estimated based on images from the HMD, companion device, and telepresence camera(s), if available. The head and body mesh may be used to generate an avatar, for example, by overlaying a texture over the head and body mesh.

In some cases, where a user of the XR system is wearing an HMD, a portion of the head may be occluded by the HMD in images taken by the companion device and/or telepresence camera(s) (if available). In such cases, it may be useful to segment the portion of a face occluded by the HMD to identify portions of images of the face that correspond to the HMD and thus occlude the face. These identified portions may be removed (e.g., overwritten by a defined color, such as white, black, etc.) for images taken by the companion device and telepresence camera(s) (if available), as shown in image 700 of FIG. 7A. In some cases, images of the removed occluded portion of the face may be provided by eye tracking cameras of the HMD, as shown in images 750 of FIG. 7B. The images 750 provided by the eye tracking cameras may be used to generate portions of the face mesh corresponding to the occluded portions of the face. In some cases, portions of the HMD may be visible in images 750 provided by the eye tracking cameras and the images 750 provided by the eye tracking cameras may also be segmented to remove portions of images 750 corresponding to the HMD. In some cases, segmenting and then removing (e.g., replacing with white pixels) the HMD may allow better recognition of facial expressions for rendering the avatar of the user. For example, existing techniques for recognizing facial expressions may be configured to handle face/body models which are not wearing an HMD and thus it may be useful to remove the HMD from images used to generate the face/body model.

In some cases, any ML model for segmentation may be used to segment the HMD from images of a user wearing the HMD. For the ML model to segment the HMD, the ML model may need to be trained to identify the HMD. FIG. 8 is a block diagram illustrating a technique 800 for providing labeled training data for segmenting a HMD from images of a user wearing the HMD, in accordance with aspects of the present disclosure. At block 802, a generated head mesh (e.g., mesh head model) may be obtained, for example, by digitally scanning heads and faces of people to generate the head meshes. In some cases, the head mesh may be obtained using any technique to digitally scan heads to generate a mesh virtual representation of the head. At block 804, a model of the HMD may be obtained. In some cases, the model of the HMD may be obtained based on computer aided design (CAD) models of the HMD. For example, during designing of the HMD, a CAD model, or other 3D software model, of the HMD may be made. This CAD model may be a 3D representation of the HMD.

At block 806, a procrustes alignment may be performed to generate a 3D head mesh fitted with the HMD at block 808. For the procrustes alignment, the HMD model may be fitted to the head mesh. In some cases, a set of vertices of the HMD model may be identified along with corresponding vertices of the head mesh where the HMD would contact. For example, if the HMD were being worn, vertices of the head mesh corresponding to the bridge of the nose, temple, any combination thereof, and the like may be identified. Based on these vertices, a pose of the HMD, such as a relative rotation and translation of the HMD with respect to a center of the face, may be determined. Based on the pose of the HMD, the HMD model may be joined to the head mesh at block 808. The head mesh with HMD model may be rendered at block 810 to generate an image of a user of the HMD wearing the HMD. In some cases, multiple images may be rendered at a variety of angles, distances, rotations, etc. As the images are rendered based on multiple virtual objects (e.g., the head mesh and HMD model), pixels of the rendered image may be labelled indicating which pixels correspond to which virtual objects at block 812. These labels may be used as ground truth labels for training a segmentation model for the HMD.

FIG. 9 is a block diagram illustrating a mesh estimation network 900 for generating a model of a user for telepresence using multiple devices, in accordance with aspects of the present disclosure. The mesh estimation network 900 may estimate a model (e.g., head and body mesh with a texture mapped on the mesh) of a user based on images captured by multiple devices (e.g., HMD, companion device, and optionally telepresence cameras). In some cases, a companion device camera 902 (and optionally telepresence cameras) may capture full body images (e.g., images including at least a head and torso) of a user, while the HMD eye tracking camera 904 may capture head images of a portion of the user's head around the eyes. In some cases, images captured by the companion device camera 902 and the HMD eye tracking camera 904 may be passed to an HMD segmentation engine 906. In some cases, there may be color/contrast variations between cameras of different devices and these variations may be normalized to reduce potential impact of these variations. The HMD segmentation engine 906 may perform color and contrast normalization to correct for any color and/or contrast differences as between the images. The HMD segmentation engine 906 may also segment images received from the companion device camera 902 and HMD eye tracking camera 904 to remove portions of the image showing the HMD. In some cases, the HMD segmentation engine 906 may be trained based training data generated using technique 800 of FIG. 8.

The segmented images from the eye tracking cameras 904 of the HMD may be passed to an eye feature extractor 908. The eye feature extractor 908 may be a portion of a ML model trained to extract features from images from the eye tracking cameras 904. For example, the eye feature extractor 908 may utilize a CNN based backbone for extracting features. Similarly, segmented images of user 916 from the companion device camera 902 (and telepresence cameras, if available) may be passed to a face feature extractor 910. The face feature extractor 910 may be another portion of the ML model trained to extract features from images from the companion device camera 902 (and telepresence cameras, if available). For example, the face feature extractor 910 may also utilize a CNN based backbone for extracting features. In some cases, images and features from the HMD eye tracking cameras 904 may be used to render a portion of a face around the eyes that may be occluded by the HMD. Similarly, images and features from the companion device camera 902 (and telepresence cameras, if available) may be used to render portions of the face that are not occluded by the HMD, such as the mouth, nose and forehead areas. The two sets of images and features may then be concatenated together (e.g., append one set of features to another set of features) to form a full face. Images and features extracted by the eye feature extractor 908 and face feature extractor 910 may be concatenated and passed to a head modeling engine 912.

The head modeling engine 912 may be another portion of the ML model trained to generate a head model 914. The head model 914 may include a mesh and corresponding texture to be mapped to the mesh, along with pose information for the cameras (e.g., companion device camera 902 and telepresence cameras, if available) relative to a center of the head. In some cases, the head model 914 may be trained to fit the images to a neutral head mesh of the user 916. For example, during an enrollment process, the HMD may be fitted to the user and images of the user's head and the HMD may be captured to generate the neutral head mesh. The head model 914 may then be trained to detect certain features in a received image, such as an edge of a mouth, tip of the nose, where the HMD would sit, etc., and fit those features to corresponding portions of the mesh. Based on how an image is mapped to the neutral head mesh, a pose of the camera that took the image may also be estimated.

In some cases, training the head modeling engine 912 may be performed by, for example, using a pose of a camera and rendering an image of the outputted head model 914. This image may then be compared to a corresponding input image to compute a loss function to train the head modeling engine 912. In some cases, training data may also be provided based on technique 800 using images with a variety of different angles and poses for the training generated images.

In some cases, images of a user 916 captured by a companion device camera 902 may be passed to a body modeling engine 918. The body modeling engine 918 may include one or more ML models for generating a model (e.g., body mesh with a texture mapped on the mesh) of the user's body. In some cases, the body modeling engine 918 may use a ML model for generating the model of the user's body. The body modeling engine 918 may output a headless body model 919. The headless body model 919 and head model 914 may be combined into a full body model 922 by a combining engine 920. The full body model 922 may then be output for use to generate an avatar for the user. In some cases, the pose information from the head model may be used to help combine the headless body model 919 and head model 914.

FIG. 10 is a flow diagram illustrating a process 1000 for managing devices for virtual telepresence, in accordance with aspects of the present disclosure. The process 1000 may be performed by a computing device (or apparatus) or a component (e.g., a chipset, codec, etc.) of the computing device, such as host processor 152 of FIG. 1, compute components 210 of FIG. 2, and/or processor 1410 of FIG. 14. The computing device may be a mobile device (e.g., a mobile phone, mobile device 1350 of FIGS. 13A and 13B, computing system 1400 of FIG. 14, etc.), a network-connected wearable such as a watch, an extended reality (XR) device such as a virtual reality (VR) device or augmented reality (AR) device (e.g., HMD 502 of FIG. 5, HMD 602 of FIG. 6, HMD 1210 of FIGS. 12A and 12B, mobile device 1350 of FIG. 13A and 13B, computing system 1400 of FIG. 14, etc.), a companion device (e.g., telepresence camera 510 or companion device 506 of FIG. 5, companion device 606 of FIG. 6, computing system 1400 of FIG. 14, etc.) vehicle or component or system of a vehicle, or other type of computing device. The operations of the process 1000 may be implemented as software components that are executed and run on one or more processors (e.g., host processor 152 of FIG. 1, compute components 210 of FIG. 2, and/or processor 1410 of FIG. 14).

At block 1002, the computing device (or component thereof) may obtain a first image from a first camera (e.g., image capture device 105A of FIG. 1, image sensor 202 of FIG. 2, image capturing device 330 of FIG. 3D, eye tracking cameras 504 of FIG. 5, HMD camera 620 and companion device camera 622 of FIG. 6, input device 1445 of FIG. 14, etc.), the first image being associated with a first capture time based on a first clock. For example, the first image may be associated (e.g., tagged) with a capture time based on a system clock of the capture device. In some cases, the computing device may include the first camera. In some cases, the computing device may be a head mounted display, a companion device, or a telepresence camera. In some cases, the computing device (or component thereof) may receive the first capture time with the first image.

At block 1004, the computing device (or component thereof) may map the first capture time to a second clock to obtain a second capture time. In some cases, the second capture time is based on a second clock. In some cases, the second clock is based on a network time. For example, the capture time based on the system clock may be mapped to a TSF time obtained from a Wi-Fi application stack. In some cases, the network time may be a timing synchronization function (TSF) time. In some cases, the computing device (or component thereof) may determine the network time and broadcast the network time.

At block 1006, the computing device (or component thereof) may associate the second capture time with the first image.

At block 1008, the computing device (or component thereof) may obtain a second image from a second camera (e.g., a camera other than the first camera, such as image capture device 105A of FIG. 1, image sensor 202 of FIG. 2, image capturing device 330 of FIG. 3D, eye tracking cameras 504 of FIG. 5, HMD camera 620 and companion device camera 622 of FIG. 6, input device 1445 of FIG. 14, etc.) of another device (e.g., different from the computing device, for example, if the computing device is an HMD, the device may be a companion device, or vice versa). In some cases, the second image including a third capture time based on the second clock.

At block 1010, the computing device (or component thereof) may determine phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image. In some cases, the phase delta information includes information to adjust the next capture time of the first camera. In some cases, computing device (or component thereof) may adjust a vertical blanking period of the first camera based on the phase delta information, for example, to speed up or slow down the next capture time of the next image. In some cases, the phase delta information includes information to adjust the next capture time of the second camera. In some cases, the computing device (or component thereof) may transmit the phase delta information to the device to adjust a vertical blanking period of the second camera.

At block 1012, the computing device (or component thereof) may output the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

FIG. 11 is a flow diagram illustrating a process 1100 for generating a full body model, in accordance with aspects of the present disclosure. In some cases, the process 1100 may be performed in conjunction with process 1000 of FIG. 10. For example, process 1000 and process 1100 may both be performed by single device as a part of generating an avatar representation. The process 1100 may be performed by a computing device (or apparatus) or a component (e.g., a chipset, codec, etc.) of the computing device, such as host processor 152 of

FIG. 1, compute components 210 of FIG. 2, and/or processor 1410 of FIG. 14. The computing device may be a mobile device (e.g., a mobile phone, mobile device 1350 of FIGS. 13A and 13B, computing system 1400 of FIG. 14, etc.), a network-connected wearable such as a watch, an extended reality (XR) device such as a virtual reality (VR) device or augmented reality (AR) device (e.g., HMD 502 of FIG. 5, HMD 602 of FIG. 6, HMD 1210 of FIGS. 12A and 12B, mobile device 1350 of FIG. 13A and 13B, computing system 1400 of FIG. 14, etc.), a companion device (e.g., telepresence camera 510 or companion device 506 of FIG. 5, companion device 606 of FIG. 6, computing system 1400 of FIG. 14, etc.) vehicle or component or system of a vehicle, or other type of computing device. The operations of the process 1100 may be implemented as software components that are executed and run on one or more processors (e.g., host processor 152 of FIG. 1, compute components 210 of FIG. 2, and/or processor 1410 of FIG. 14).

At block 1102, the computing device (or component thereof) may obtain a third image (e.g., from a camera of a companion device, such as telepresence camera 510 or companion device 506 of FIG. 5, companion device 606 of FIG. 6, etc.), the third image including at least a head and torso of a person. In some cases, the computing device (or component thereof) may normalize a color of the third image.

At block 1104, the computing device (or component thereof) may extract a first set of features from the third image.

At block 1106, the computing device (or component thereof) may obtain a fourth image, the fourth image including a portion of a head around eyes of the person (e.g., images 750 of FIG. 7B). In some cases, the computing device (or component thereof) may segment the third image and the fourth image to identify portions of the third image and the fourth image corresponding to a head mounted display (HMD) (e.g., by an HMD segmentation engine). In some cases, the computing device (or component thereof) may segment the third image and the fourth image using a machine learning model for segmenting the HMD. In some cases, the machine learning model for segmenting the HMD is trained based on a generated head mesh and a model of the HMD. In some cases, the generated head mesh is generated by digitally scanning a head of a person. In some cases, the model of the HMD comprises a computer aided design (CAD) model of the HMD. In some cases, the model of the HMD is joined to the generated head mesh to form a joined model. In some cases, the joined model provides a ground truth for training the machine learning model.

At block 1108, the computing device (or component thereof) may extract a second set of features from the fourth image. In some cases, the computing device (or component thereof) may concatenate the first set of features and the second set of features.

At block 1110, the computing device (or component thereof) may generate a head model (e.g., head model 914) based on the first set of features and second set of features, the head model including pose information for a camera that captured the third image. In some cases, the computing device (or component thereof) may generate the head model based on the concatenated first set of features and second set of features. In some cases, the head model includes a mesh model of the head and corresponding texture.

At block 1112, the computing device (or component thereof) may generate a body model (e.g., body model 919) based on the third image.

At block 1114, the computing device (or component thereof) may combine the head model and body model into a full body model (e.g., full body model 922).

At block 1116, the computing device (or component thereof) may output the full body model.

FIG. 12A is a perspective diagram 1200 illustrating a head-mounted display (HMD) 1210, in accordance with some examples. The HMD 1210 may be, for example, an augmented reality (AR) headset, a virtual reality (VR) headset, a mixed reality (MR) headset, an extended reality (XR) headset, or some combination thereof. The HMD 1210 may be an example of an XR system 200, a SLAM system, or a combination thereof. The HMD 1210 includes a first camera 1230A and a second camera 1230B along a front portion of the HMD 1210. In some examples, the HMD 1210 may only have a single camera. In some examples, the HMD 1210 may include one or more additional cameras in addition to the first camera 1230A and the second camera 1230B. In some examples, the HMD 1210 may include one or more additional sensors in addition to the first camera 1230A and the second camera 1230B.

FIG. 12B is a perspective diagram 1230 illustrating the head-mounted display (HMD) 1210 of FIG. 12A being worn by a user 1220, in accordance with some examples. The user 1220 wears the HMD 1210 on the user 1220′s head over the user 1220′s eyes. The HMD 1210 can capture images with the first camera 1230A and the second camera 1230B. In some examples, the HMD 1210 displays one or more display images toward the user 1220′s eyes that are based on the images captured by the first camera 1230A and the second camera 1230B. The display images may provide a stereoscopic view of the environment, in some cases with information overlaid and/or with other modifications. For example, the HMD 1210 can display a first display image to the user 1220′s right eye, the first display image based on an image captured by the first camera 1230A. The HMD 1210 can display a second display image to the user 1220′s left eye, the second display image based on an image captured by the second camera 1230B. For instance, the HMD 1210 may provide overlaid information in the display images overlaid over the images captured by the first camera 1230A and the second camera 1230B.

The HMD 1210 may include no wheels, propellers or other conveyance of its own. Instead, the HMD 1210 relies on the movements of the user 1220 to move the HMD 1210 about the environment. In some cases, for instance where the HMD 1210 is a VR headset, the environment may be entirely or partially virtual. If the environment is at least partially virtual, then movement through the virtual environment may be virtual as well. For instance, movement through the virtual environment can be controlled by an input device 208. The movement actuator may include any such input device 208. Movement through the virtual environment may not require wheels, propellers, legs, or any other form of conveyance. Even if an environment is virtual, SLAM techniques may still be valuable, as the virtual environment can be unmapped and/or may have been generated by a device other than the HMD 1210, such as a remote server or console associated with a video game or video game platform.

FIG. 13A is a perspective diagram 1300 illustrating a front surface 1355 of a mobile device 1350 that performs features described here, including, for example, feature tracking and/or visual simultaneous localization and mapping (VSLAM) using one or more front-facing cameras 1330A-B, in accordance with some examples. The mobile device 1350 may be, for example, a cellular telephone, a satellite phone, a portable gaming console, a music player, a health tracking device, a wearable device, a wireless communication device, a laptop, a mobile device, any other type of computing device or computing system (e.g., computing system 1400 of FIG. 14) discussed herein, or a combination thereof. The front surface 1355 of the mobile device 1350 includes a display screen 1345. The front surface 1355 of the mobile device 1350 includes a first camera 1330A and a second camera 1330B. The first camera 1330A and the second camera 1330B are illustrated in a bezel around the display screen 1345 on the front surface 1355 of the mobile device 1350. In some examples, the first camera 1330A and the second camera 1330B can be positioned in a notch or cutout that is cut out from the display screen 1345 on the front surface 1355 of the mobile device 1350. In some examples, the first camera 1330A and the second camera 1330B can be under-display cameras that are positioned between the display screen 1345 and the rest of the mobile device 1350, so that light passes through a portion of the display screen 1345 before reaching the first camera 1330A and the second camera 1330B. The first camera 1330A and the second camera 1330B of the perspective diagram 1300 are front-facing cameras. The first camera 1330A and the second camera 1330B face a direction perpendicular to a planar surface of the front surface 1355 of the mobile device 1350. In some examples, the front surface 1355 of the mobile device 1350 may only have a single camera. In some examples, the mobile device 1350 may include one or more additional cameras in addition to the first camera 1330A and the second camera 1330B. In some examples, the mobile device 1350 may include one or more additional sensors in addition to the first camera 1330A and the second camera 1330B.

FIG. 13B is a perspective diagram 1310 illustrating a rear surface 1365 of a mobile device 1350. The mobile device 1350 includes a third camera 1330C and a fourth camera 1330D on the rear surface 1365 of the mobile device 1350. The third camera 1330C and the fourth camera 1330D of the perspective diagram 1310 are rear-facing. The third camera 1330C and the fourth camera 1330D face a direction perpendicular to a planar surface of the rear surface 1365 of the mobile device 1350. While the rear surface 1365 of the mobile device 1350 does not have a display screen 1345 as illustrated in the perspective diagram 1310, in some examples, the rear surface 1365 of the mobile device 1350 may have a second display screen. If the rear surface 1365 of the mobile device 1350 has a display screen 1345, any positioning of the third camera 1330C and the fourth camera 1330D relative to the display screen 1345 may be used as discussed with respect to the first camera 1330A and the second camera 1330B at the front surface 1355 of the mobile device 1350. In some examples, the rear surface 1365 of the mobile device 1350 may only have a single camera. In some examples, the mobile device 1350 may include one or more additional cameras in addition to the first camera 1330A, the second camera 1330B, the third camera 1330C, and the fourth camera 1330D. In some examples, the mobile device 1350 may include one or more additional sensors in addition to the first camera 1330A, the second camera 1330B, the third camera 1330C, and the fourth camera 1330D.

Like the HMD 1210, the mobile device 1350 includes no wheels, propellers, or other conveyance of its own. Instead, the mobile device 1350 relies on the movements of a user holding or wearing the mobile device 1350 to move the mobile device 1350 about the environment. In some cases, for instance where the mobile device 1350 is used for AR, VR, MR, or XR, the environment may be entirely or partially virtual. In some cases, the mobile device 1350 may be slotted into a head-mounted device (HMD) (e.g., into a cradle of the HMD) so that the mobile device 1350 functions as a display of the HMD, with the display screen 1345 of the mobile device 1350 functioning as the display of the HMD. If the environment is at least partially virtual, then movement through the virtual environment may be virtual as well. For instance, movement through the virtual environment can be controlled by one or more joysticks, buttons, video game controllers, mice, keyboards, trackpads, and/or other input devices that are coupled in a wired or wireless fashion to the mobile device 1350.

FIG. 14 is a diagram illustrating an example of a system for implementing certain aspects of the present technology. In particular, FIG. 14 illustrates an example of computing system 1400, which can be for example any computing device making up internal computing system, a remote computing system, a camera, or any component thereof in which the components of the system are in communication with each other using connection 1405. Connection 1405 can be a physical connection using a bus, or a direct connection into processor 1410, such as in a chipset architecture. Connection 1405 can also be a virtual connection, networked connection, or logical connection.

In some examples, computing system 1400 is a distributed system in which the functions described in this disclosure can be distributed within a datacenter, multiple data centers, a peer network, etc. In some examples, one or more of the described system components represents many such components each performing some or all of the functions for which the component is described. In some cases, the components can be physical or virtual devices.

Example system 1400 includes at least one processing unit (CPU or processor) 1410 and connection 1405 that couples various system components including system memory 1415, such as read-only memory (ROM) 1420 and random access memory (RAM) 1425 to processor 1410. Computing system 1400 can include a cache 1412 of high-speed memory connected directly with, in close proximity to, or integrated as part of processor 1410.

Processor 1410 can include any general purpose processor and a hardware service or software service, such as services 1432, 1434, and 1436 stored in storage device 1430, configured to control processor 1410 as well as a special-purpose processor where software instructions are incorporated into the actual processor design. Processor 1410 may be a completely self-contained computing system, containing multiple cores or processors, a bus, memory controller, cache, etc. A multi-core processor may be symmetric or asymmetric.

To enable user interaction, computing system 1400 includes an input device 1445, which can represent any number of input mechanisms, such as a microphone for speech, a touch-sensitive screen for gesture or graphical input, keyboard, mouse, motion input, speech, camera, accelerometers, gyroscopes, etc. Computing system 1400 can also include output device 1435, which can be one or more of a number of output mechanisms. In some instances, multimodal systems can enable a user to provide multiple types of input/output to communicate with computing system 1400. Computing system 1400 can include communications interface 1440, which can generally govern and manage the user input and system output. The communication interface may perform or facilitate receipt and/or transmission of wired or wireless communications using wired and/or wireless transceivers, including those making use of an audio jack/plug, a microphone jack/plug, a universal serial bus (USB) port/plug, an Apple® Lightning® port/plug, an Ethernet port/plug, a fiber optic port/plug, a proprietary wired port/plug, a BLUETOOTH® wireless signal transfer, a BLUETOOTH® low energy (BLE) wireless signal transfer, an IBEACON® wireless signal transfer, a radio-frequency identification (RFID) wireless signal transfer, near-field communications (NFC) wireless signal transfer, dedicated short range communication (DSRC) wireless signal transfer, 802.11 Wi-Fi wireless signal transfer, wireless local area network (WLAN) signal transfer, Visible Light Communication (VLC), Worldwide Interoperability for Microwave Access (WiMAX), Infrared (IR) communication wireless signal transfer, Public Switched Telephone Network (PSTN) signal transfer, Integrated Services Digital Network (ISDN) signal transfer, 3G/4G/5G/LTE cellular data network wireless signal transfer, ad-hoc network signal transfer, radio wave signal transfer, microwave signal transfer, infrared signal transfer, visible light signal transfer, ultraviolet light signal transfer, wireless signal transfer along the electromagnetic spectrum, or some combination thereof. The communications interface 1440 may also include one or more Global Navigation Satellite System (GNSS) receivers or transceivers that are used to determine a location of the computing system 1400 based on receipt of one or more signals from one or more satellites associated with one or more GNSS systems. GNSS systems include, but are not limited to, the US-based Global Positioning System (GPS), the Russia-based Global Navigation Satellite System (GLONASS), the China-based BeiDou Navigation Satellite System (BDS), and the Europe-based Galileo GNSS. There is no restriction on operating on any particular hardware arrangement, and therefore the basic features here may easily be substituted for improved hardware or firmware arrangements as they are developed.

Storage device 1430 can be a non-volatile and/or non-transitory and/or computer-readable memory device and can be a hard disk or other types of computer readable media which can store data that are accessible by a computer, such as magnetic cassettes, flash memory cards, solid state memory devices, digital versatile disks, cartridges, a floppy disk, a flexible disk, a hard disk, magnetic tape, a magnetic strip/stripe, any other magnetic storage medium, flash memory, memristor memory, any other solid-state memory, a compact disc read only memory (CD-ROM) optical disc, a rewritable compact disc (CD) optical disc, digital video disk (DVD) optical disc, a blu-ray disc (BDD) optical disc, a holographic optical disk, another optical medium, a secure digital (SD) card, a micro secure digital (microSD) card, a Memory Stick® card, a smartcard chip, a EMV chip, a subscriber identity module (SIM) card, a mini/micro/nano/pico SIM card, another integrated circuit (IC) chip/card, random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash EPROM (FLASHEPROM), cache memory (L1/L2/L3/L4/L5/L#), resistive random-access memory (RRAM/ReRAM), phase change memory (PCM), spin transfer torque RAM (STT-RAM), another memory chip or cartridge, and/or a combination thereof.

The storage device 1430 can include software services, servers, services, etc., that when the code that defines such software is executed by the processor 1410, it causes the system to perform a function. In some examples, a hardware service that performs a particular function can include the software component stored in a computer-readable medium in connection with the necessary hardware components, such as processor 1410, connection 1405, output device 1435, etc., to carry out the function.

As used herein, the term “computer-readable medium” includes, but is not limited to, portable or non-portable storage devices, optical storage devices, and various other mediums capable of storing, containing, or carrying instruction(s) and/or data. A computer-readable medium may include a non-transitory medium in which data can be stored and that does not include carrier waves and/or transitory electronic signals propagating wirelessly or over wired connections. Examples of a non-transitory medium may include, but are not limited to, a magnetic disk or tape, optical storage media such as compact disk (CD) or digital versatile disk (DVD), flash memory, memory or memory devices. A computer-readable medium may have stored thereon code and/or machine-executable instructions that may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted using any suitable means including memory sharing, message passing, token passing, network transmission, or the like.

In some examples, the computer-readable storage devices, mediums, and memories can include a cable or wireless signal containing a bit stream and the like. However, when mentioned, non-transitory computer-readable storage media expressly exclude media such as energy, carrier signals, electromagnetic waves, and signals per se.

Specific details are provided in the description above to provide a thorough understanding of the examples provided herein. However, it will be understood by one of ordinary skill in the art that the examples may be practiced without these specific details. For clarity of explanation, in some instances the present technology may be presented as including individual functional blocks including functional blocks comprising devices, device components, steps or routines in a method embodied in software, or combinations of hardware and software. Additional components may be used other than those shown in the figures and/or described herein. For example, circuits, systems, networks, processes, and other components may be shown as components in block diagram form in order not to obscure the examples in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the examples.

Individual examples may be described above as a process or method which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed, but could have additional steps not included in a figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination can correspond to a return of the function to the calling function or the main function.

Processes and methods according to the above-described examples can be implemented using computer-executable instructions that are stored or otherwise available from computer-readable media. Such instructions can include, for example, instructions and data which cause or otherwise configure a general purpose computer, special purpose computer, or a processing device to perform a certain function or group of functions. Portions of computer resources used can be accessible over a network. The computer executable instructions may be, for example, binaries, intermediate format instructions such as assembly language, firmware, source code, etc. Examples of computer-readable media that may be used to store instructions, information used, and/or information created during methods according to described examples include magnetic or optical disks, flash memory, USB devices provided with non-volatile memory, networked storage devices, and so on.

Devices implementing processes and methods according to these disclosures can include hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof, and can take any of a variety of form factors. When implemented in software, firmware, middleware, or microcode, the program code or code segments to perform the necessary tasks (e.g., a computer-program product) may be stored in a computer-readable or machine-readable medium. A processor(s) may perform the necessary tasks. Typical examples of form factors include laptops, smart phones, mobile phones, tablet devices or other small form factor personal computers, personal digital assistants, rackmount devices, standalone devices, and so on. Functionality described herein also can be embodied in peripherals or add-in cards. Such functionality can also be implemented on a circuit board among different chips or different processes executing in a single device, by way of further example.

The instructions, media for conveying such instructions, computing resources for executing them, and other structures for supporting such computing resources are example means for providing the functions described in the disclosure.

In the foregoing description, aspects of the application are described with reference to specific examples thereof, but those skilled in the art will recognize that the application is not limited thereto. Thus, while illustrative examples of the application have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art. Various features and aspects of the above-described application may be used individually or jointly. Further, examples can be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of the specification. The specification and drawings are, accordingly, to be regarded as illustrative rather than restrictive. For the purposes of illustration, methods were described in a particular order. It should be appreciated that in alternate examples, the methods may be performed in a different order than that described.

One of ordinary skill will appreciate that the less than (“<”) and greater than (“>”) symbols or terminology used herein can be replaced with less than or equal to (“≤”) and greater than or equal to (“≥”) symbols, respectively, without departing from the scope of this description.

Where components are described as being “configured to” perform certain operations, such configuration can be accomplished, for example, by designing electronic circuits or other hardware to perform the operation, by programming programmable electronic circuits (e.g., microprocessors, or other suitable electronic circuits) to perform the operation, or any combination thereof.

The phrase “coupled to” refers to any component that is physically connected to another component either directly or indirectly, and/or any component that is in communication with another component (e.g., connected to the other component over a wired or wireless connection, and/or other suitable communication interface) either directly or indirectly.

Claim language or other language reciting “at least one of” a set and/or “one or more” of a set indicates that one member of the set or multiple members of the set (in any combination) satisfy the claim. For example, claim language reciting “at least one of A and B” means A, B, or A and B. In another example, claim language reciting “at least one of A, B, and C” means A, B, C, or A and B, or A and C, or B and C, or A and B and C. The language “at least one of” a set and/or “one or more” of a set does not limit the set to the items listed in the set. For example, claim language reciting “at least one of A and B” can mean A, B, or A and B, and can additionally include items not listed in the set of A and B.

Claim language or other language reciting “at least one processor configured to,” “at least one processor being configured to,” “a processor configured to,” or the like indicates that one processor or multiple processors (in any combination) can perform the associated operation(s). For example, claim language reciting “at least one processor configured to: X, Y, and Z” means a single processor can be used to perform operations X, Y, and Z; or that multiple processors are each tasked with a certain subset of operations X, Y, and Z such that together the multiple processors perform X, Y, and Z; or that a group of multiple processors work together to perform operations X, Y, and Z. In another example, claim language reciting “at least one processor configured to: X, Y, and Z” can mean that any single processor may only perform at least a subset of operations X, Y, and Z.

The various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the examples disclosed herein may be implemented as electronic hardware, computer software, firmware, or combinations thereof. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

The techniques described herein may also be implemented in electronic hardware, computer software, firmware, or any combination thereof. Such techniques may be implemented in any of a variety of devices such as general purposes computers, wireless communication device handsets, or integrated circuit devices having multiple uses including application in wireless communication device handsets and other devices. Any features described as modules or components may be implemented together in an integrated logic device or separately as discrete but interoperable logic devices. If implemented in software, the techniques may be realized at least in part by a computer-readable data storage medium comprising program code including instructions that, when executed, performs one or more of the methods described above. The computer-readable data storage medium may form part of a computer program product, which may include packaging materials. The computer-readable medium may comprise memory or data storage media, such as random access memory (RAM) such as synchronous dynamic random access memory (SDRAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), FLASH memory, magnetic or optical data storage media, and the like. The techniques additionally, or alternatively, may be realized at least in part by a computer-readable communication medium that carries or communicates program code in the form of instructions or data structures and that can be accessed, read, and/or executed by a computer, such as propagated signals or waves.

The program code may be executed by a processor, which may include one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, an application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Such a processor may be configured to perform any of the techniques described in this disclosure. A general purpose processor may be a microprocessor; but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. Accordingly, the term “processor,” as used herein may refer to any of the foregoing structure, any combination of the foregoing structure, or any other structure or apparatus suitable for implementation of the techniques described herein. In addition, in some aspects, the functionality described herein may be provided within dedicated software modules or hardware modules configured for encoding and decoding, or incorporated in a combined video encoder-decoder (CODEC).

Illustrative aspects of the present disclosure include:

Aspect 1. An augmented reality apparatus, comprising: a memory; and a processor coupled to the memory, wherein the processor is configured to: obtain a first image from a first camera, the first image being associated with a first capture time based on a first clock; map the first capture time to a second clock to obtain a second capture time, and wherein the second clock is based on a network time; associate the second capture time with the first image; obtain a second image from a second camera of another device, the second image including a third capture time based on the second clock; determine phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; and output the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

Aspect 2. The augmented reality apparatus of Aspect 1, wherein the augmented reality apparatus further comprises the first camera.

Aspect 3. The augmented reality apparatus of any of Aspects 1-2, wherein: the phase delta information includes information to adjust the next capture time of the first camera; and the processor is configured to adjust a vertical blanking period of the first camera based on the phase delta information.

Aspect 4. The augmented reality apparatus of any of Aspects 1-3, wherein the processor is further configured to: determine the network time; and broadcast the network time.

Aspect 5. The augmented reality apparatus of any of Aspects 1-4, wherein: the phase delta information includes information to adjust the next capture time of the second camera; and the processor is configured to transmit the phase delta information to the another device to adjust a vertical blanking period of the second camera.

Aspect 6. The augmented reality apparatus of any of Aspects 1-5, wherein the device comprises at least one of a head mounted display, a companion device, or a telepresence camera.

Aspect 7. The augmented reality apparatus of any of Aspects 1-6, wherein the network time comprises a timing synchronization function (TSF) time.

Aspect 8. The augmented reality apparatus of any of Aspects 1-7, wherein the processor is further configured to: obtain a third image, the third image including at least a head and torso of a person; extract a first set of features from the third image; obtain a fourth image, the fourth image including a portion of a head around eyes of the person; extract a second set of features from the fourth image; generate a head model based on the first set of features and second set of features, the head model including pose information for a camera that captured the third image; generate a body model based on the third image; combine the head model and body model into a full body model; and output the full body model.

Aspect 9. The augmented reality apparatus of Aspect 8, wherein the processor is further configured to concatenate the first set of features and the second set of features.

Aspect 10. The augmented reality apparatus of Aspect 9, wherein the processor is further configured to generate the head model based on the concatenated first set of features and second set of features.

Aspect 11. The augmented reality apparatus of any of Aspects 8-10, wherein the processor is further configured to normalize a color of the third image.

Aspect 12. The augmented reality apparatus of any of Aspects 8-11, wherein the head model further includes a mesh model of the head and corresponding texture.

Aspect 13. The augmented reality apparatus of any of Aspects 8-12, wherein the processor is further configured to segment the third image and the fourth image to identify portions of the third image and the fourth image corresponding to a head mounted display (HMD).

Aspect 14. The augmented reality apparatus of Aspect 13, wherein the processor is configured to segment the third image and the fourth image using a machine learning model for segmenting the HMD.

Aspect 15. The augmented reality apparatus of Aspect 14, wherein the machine learning model for segmenting the HMD is trained based on a generated head mesh and a model of the HMD.

Aspect 16. The augmented reality apparatus of Aspect 15, wherein the generated head mesh is generated by digitally scanning a head of a person.

Aspect 17. The augmented reality apparatus of any of Aspects 15-16, wherein the model of the HMD is based on a computer aided design (CAD) model of the HMD.

Aspect 18. The augmented reality apparatus of any of Aspects 15-17, wherein the model of the HMD is joined to the generated head mesh to form a joined model.

Aspect 19. The augmented reality apparatus of Aspect 18, wherein the joined model provides a ground truth for training the machine learning model.

Aspect 20. The augmented reality apparatus of any of Aspects 1-19, wherein the processor is further configured to receive the first capture time with the first image.

Aspect 21. A method for image capture by a first device, comprising: obtaining a first image from a first camera, the first image being associated with a first capture time based on a first clock; mapping the first capture time to a second clock to obtain a second capture time, wherein the second clock is based on a network time; associating the second capture time with the first image; obtaining a second image from a second camera of a second device, the second image including a third capture time based on the second clock; determining phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; and outputting the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

Aspect 22. The method of Aspect 21, wherein the first device includes the first camera.

Aspect 23. The method of any of Aspects 21-22, wherein the phase delta information includes information to adjust the next capture time of the first camera, and further comprising adjusting a vertical blanking period of the first camera based on the phase delta information.

Aspect 24. The method of any of Aspects 21-23, further comprising: determining the network time; and broadcasting the network time.

Aspect 25. The method of any of Aspects 21-24, wherein the phase delta information includes information to adjust the next capture time of the second camera; and further comprising transmitting the phase delta information to the second device to adjust a vertical blanking period of the second camera.

Aspect 26. The method of any of Aspects 21-25, wherein the first device comprises at least one of a head mounted display, a companion device, or a telepresence camera.

Aspect 27. The method of any of Aspects 21-26, wherein the network time comprises a timing synchronization function (TSF) time.

Aspect 28. The method of any of Aspects 21-27, further comprising: obtaining a third image, the third image including at least a head and torso of a person; extracting a first set of features from the third image; obtaining a fourth image, the fourth image including a portion of a head around eyes of the person; extracting a second set of features from the fourth image; generating a head model based on the first set of features and second set of features, the head model including pose information for a camera that captured the third image; generating a body model based on the third image; combining the head model and body model into a full body model; and outputting the full body model.

Aspect 29. The method of Aspect 28, further comprising concatenating the first set of features and the second set of features.

Aspect 30. The method of Aspect 29, further comprising generating the head model based on the concatenated first set of features and second set of features.

Aspect 31. The method of any of Aspects 28-30, further comprising normalizing a color of the third image.

Aspect 32. The method of any of Aspects 28-31, wherein the head model further includes a mesh model of the head and corresponding texture.

Aspect 33. The method of any of Aspects 28-32, further comprising segmenting the third image and the fourth image to identify portions of the third image and the fourth image corresponding to a head mounted display (HMD).

Aspect 34. The method of Aspect 33, further comprising segment the third image and the fourth image using a machine learning model for segmenting the HMD.

Aspect 35. The method of Aspect 34, wherein the machine learning model for segmenting the HMD is trained based on a generated head mesh and a model of the HMD.

Aspect 36. The method of Aspect 35, wherein the generated head mesh is generated by digitally scanning a head of a person.

Aspect 37. The method of any of Aspects 35-36, wherein the model of the HMD is based on a computer aided design (CAD) model of the HMD.

Aspect 38. The method of any of Aspects 35-37, wherein the model of the HMD is joined to the generated head mesh to form a joined model.

Aspect 39. The method of Aspect 38, wherein the joined model provides a ground truth for training the machine learning model.

Aspect 40. The method of any of Aspects 21-39, further comprising receiving the first capture time with the first image.

Aspect 41. A non-transitory computer-readable medium having stored thereon instructions that, when executed by at least one processor, cause the at least one processor to: obtain a first image from a first camera, the first image being associated with a first capture time based on a first clock; map the first capture time to a second clock to obtain a second capture time, wherein the second clock is based on a network time; associate the second capture time with the first image; obtain a second image from a second camera of a second device, the second image including a third capture time based on the second clock; determine phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; and output the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

Aspect 42. The non-transitory computer-readable medium of Aspect 41, wherein the instructions are executed by the at least one processor of a first device, and wherein the first device includes the first camera.

Aspect 43. The non-transitory computer-readable medium of any of Aspects 41-42, wherein: the phase delta information includes information to adjust the next capture time of the first camera; and the instructions further cause the at least one processor to adjust a vertical blanking period of the first camera based on the phase delta information.

Aspect 44. The non-transitory computer-readable medium of any of Aspects 41-43, the instructions further cause the at least one processor to: determine the network time; and broadcast the network time.

Aspect 45. The non-transitory computer-readable medium of any of Aspects 41-44, wherein: the phase delta information includes information to adjust the next capture time of the second camera; and the instructions further cause the at least one processor to transmit the phase delta information to the second device to adjust a vertical blanking period of the second camera.

Aspect 46. The non-transitory computer-readable medium of any of Aspects 42-45, wherein the second device comprises at least one of a head mounted display, a companion device, or a telepresence camera.

Aspect 47. The non-transitory computer-readable medium of any of Aspects 41-46, wherein the network time comprises a timing synchronization function (TSF) time.

Aspect 48. The non-transitory computer-readable medium of any of Aspects 41-47, wherein the instructions further cause the at least one processor to: obtain a third image, the third image including at least a head and torso of a person; extract a first set of features from the third image; obtain a fourth image, the fourth image including a portion of a head around eyes of the person; extract a second set of features from the fourth image; generate a head model based on the first set of features and second set of features, the head model including pose information for a camera that captured the third image; generate a body model based on the third image; combine the head model and body model into a full body model; and output the full body model.

Aspect 49. The non-transitory computer-readable medium of Aspect 48, wherein the instructions further cause the at least one processor to concatenate the first set of features and the second set of features.

Aspect 50. The non-transitory computer-readable medium of Aspect 49, wherein the instructions further cause the at least one processor to generate the head model based on the concatenated first set of features and second set of features.

Aspect 51. The non-transitory computer-readable medium of any of Aspects 48-50, wherein the instructions further cause the at least one processor to normalize a color of the third image.

Aspect 52. The non-transitory computer-readable medium of any of Aspects 48-51, wherein the head model further includes a mesh model of the head and corresponding texture.

Aspect 53. The non-transitory computer-readable medium of any of Aspects 48-52, wherein the instructions further cause the at least one processor to segment the third image and the fourth image to identify portions of the third image and the fourth image corresponding to a head mounted display (HMD).

Aspect 54. The non-transitory computer-readable medium of Aspect 53, wherein the instructions further cause the at least one processor to segment the third image and the fourth image using a machine learning model for segmenting the HMD.

Aspect 55. The non-transitory computer-readable medium of Aspect 54, wherein the machine learning model for segmenting the HMD is trained based on a generated head mesh and a model of the HMD.

Aspect 56. The non-transitory computer-readable medium of Aspect 55, wherein the generated head mesh is generated by digitally scanning a head of a person.

Aspect 57. The non-transitory computer-readable medium of any of Aspects 55-56, wherein the model of the HMD is based on a computer aided design (CAD) model of the HMD.

Aspect 58. The non-transitory computer-readable medium of any of Aspects 55-67, wherein the model of the HMD is joined to the generated head mesh to form a joined model.

Aspect 59. The non-transitory computer-readable medium of Aspect 58, wherein the joined model provides a ground truth for training the machine learning model.

Aspect 60. The non-transitory computer-readable medium of any of Aspects 41-59, wherein the instructions further cause the at least one processor to receive the first capture time with the first image.

Aspect 61. An apparatus for image capture, comprising one or more means for performing operations according to any of Aspects 21-40.

Claims

1. An augmented reality apparatus, comprising: a memory; anda processor coupled to the memory, wherein the processor is configured to: obtain a first image from a first camera, the first image being associated with a first capture time based on a first clock;map the first capture time to a second clock to obtain a second capture time, wherein the second clock is based on a network time;associate the second capture time with the first image;obtain a second image from a second camera of another device, the second image including a third capture time based on the second clock;determine phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; andoutput the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

2. The augmented reality apparatus of claim 1, wherein the augmented reality apparatus further comprises the first camera.

3. The augmented reality apparatus of claim 1, wherein: the phase delta information includes information to adjust the next capture time of the first camera; andthe processor is configured to adjust a vertical blanking period of the first camera based on the phase delta information.

4. The augmented reality apparatus of claim 1, wherein the processor is further configured to: determine the network time; andbroadcast the network time.

5. The augmented reality apparatus of claim 1, wherein: the phase delta information includes information to adjust the next capture time of the second camera; andthe processor is configured to transmit the phase delta information to the another device to adjust a vertical blanking period of the second camera.

6. The augmented reality apparatus of claim 1, wherein the network time comprises a timing synchronization function (TSF) time.

7. The augmented reality apparatus of claim 1, wherein the processor is further configured to: obtain a third image, the third image including at least a head and torso of a person;extract a first set of features from the third image;obtain a fourth image, the fourth image including a portion of a head around eyes of the person;extract a second set of features from the fourth image;generate a head model based on the first set of features and second set of features, the head model including pose information for a camera that captured the third image;generate a body model based on the third image;combine the head model and body model into a full body model; andoutput the full body model.

8. The augmented reality apparatus of claim 7, wherein the processor is further configured to concatenate the first set of features and the second set of features.

9. The augmented reality apparatus of claim 8, wherein the processor is further configured to generate the head model based on the concatenated first set of features and second set of features.

10. The augmented reality apparatus of claim 7, wherein the processor is further configured to normalize a color of the third image.

11. The augmented reality apparatus of claim 7, wherein the head model further includes a mesh model of the head and corresponding texture.

12. The augmented reality apparatus of claim 7, wherein the processor is further configured to segment the third image and the fourth image to identify portions of the third image and the fourth image corresponding to a head mounted display (HMD).

13. The augmented reality apparatus of claim 12, wherein the processor is configured to segment the third image and the fourth image using a machine learning model for segmenting the HMD, and wherein the machine learning model for segmenting the HMD is trained based on a generated head mesh and a model of the HMD.

14. The augmented reality apparatus of claim 13, wherein the model of the HMD is based on a computer aided design (CAD) model of the HMD.

15. The augmented reality apparatus of claim 13, wherein the model of the HMD is joined to the generated head mesh to form a joined model that provides a ground truth for training the machine learning model.

16. A method for image capture by a first device, comprising: obtaining a first image from a first camera, the first image being associated with a first capture time based on a first clock;mapping the first capture time to a second clock to obtain a second capture time, wherein the second clock is based on a network time;associating the second capture time with the first image;obtaining a second image from a second camera of a second device, the second image including a third capture time based on the second clock;determining phase delta information based on a time difference between the second capture time associated with the first image and the third capture time of the second image; andoutputting the phase delta information to adjust a next capture time of at least one of the first camera or the second camera.

17. The method of claim 16, wherein the phase delta information includes information to adjust the next capture time of the first camera, and further comprising adjusting a vertical blanking period of the first camera based on the phase delta information.

18. The method of claim 16, further comprising: determining the network time; andbroadcasting the network time.

19. The method of claim 16, wherein the phase delta information includes information to adjust the next capture time of the second camera; and further comprising transmitting the phase delta information to the second device to adjust a vertical blanking period of the second camera

20. The method of claim 16, further comprising: obtaining a third image, the third image including at least a head and torso of a person;extracting a first set of features from the third image;obtaining a fourth image, the fourth image including a portion of a head around eyes of the person;extracting a second set of features from the fourth image;generating a head model based on the first set of features and second set of features, the head model including pose information for a camera that captured the third image;generating a body model based on the third image;combining the head model and body model into a full body model; andoutputting the full body model.