Patent Grant
11622066
The instant disclosure is related to digital photography and more specifically to a flash array for a portable camera system.
Portable camera systems are popular and nearly ubiquitous in portable smart apparatus such as smart phones. In many smart phones, the flash is designed as a spotlight source which may lead to stark shadows and reflections. Professional photographers may use a reflector to diffusely illuminate a scene and capture images with softer illumination.
In one embodiment, a distributed light source couple-able to a mobile device, comprising, a distributed array of light emitting points and a mount connected to the distributed array and couple-able to the mobile device, the distributed array capable of light emission from a plurality of areas.
In another embodiment, a distributed light source couple-able to a mobile device, comprising, a light gathering layer that gathers light from at least one light source, a distributed array of light emitting optical foci optically coupled to the light gathering layer wherein the distributed array gathers light from the light gathering layer and outputs the light from the light emitting optical foci and a mount connected to the distributed array and couple-able to the mobile device, the distributed array capable of light emission from a plurality of areas.
In the drawings:
The embodiments listed below are written only to illustrate the applications of this apparatus and method, not to limit the scope. The equivalent form of modifications towards this apparatus and method shall be categorized as within the scope the claims.
Certain terms are used throughout the following description and claims to refer to particular system components. As one skilled in the art will appreciate, different companies may refer to a component and/or method by different names. This document does not intend to distinguish between components and/or methods that differ in name but not in function.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device that connection may be through a direct connection or through an indirect connection via other devices and connections.
Electronic system 100 may include various types of computer readable media and interfaces for various other types of computer readable media. In the depicted example, electronic system 100 includes a bus 112, processor(s) 120, a system memory 114, a read-only memory (RON) 118, a permanent storage device 110, an input device interface 122, an output device interface 116, and one or more network interfaces 124. In some implementations, electronic system 100 may include or be integrated with other computing devices or circuitry for operation of the various components and processes previously described. In one embodiment of the present disclosure the processor(s) 120 is coupled through the bus 112 to a camera module sensor 126 and a distributed flash array 128.
Bus 112 collectively represents all system, peripheral, and chipset buses that communicatively connect the numerous internal devices of electronic system 100. For instance, bus 112 communicatively connects processor(s) 120 with ROM 118, system memory 114, permanent storage device 110, a camera module sensor 126 and a distributed flash array 128.
From these various memory units, processor(s) 120 retrieves instructions to execute and data to process in order to execute the processes of the subject disclosure. The processing unit(s) can be a single processor or a multi-core processor in different implementations.
ROM 118 stores static data and instructions that are needed by processor(s) 120 and other modules of the electronic system. Permanent storage device 110, on the other hand, is a read-and-write memory device. This device is a non-volatile memory unit that stores instructions and data even when electronic system 100 is off. Some implementations of the subject disclosure use a mass-storage device (such as a magnetic or optical disk and its corresponding disk drive) as permanent storage device 110.
Other implementations use a removable storage device (such as a floppy disk, flash drive, and its corresponding disk drive) as permanent storage device 110. Like permanent storage device 110, system memory 114 is a read-and-write memory device. However, unlike permanent storage device 110, system memory 114 is a volatile read-and-write memory, such a random access memory. System memory 114 stores some of the instructions and data that the processor needs at runtime. In some implementations, the processes of the subject disclosure are stored in system memory 114, permanent storage device 110, and/or ROM 118. From these various memory units, processor(s) 120 retrieves instructions to execute and data to process in order to execute the processes of some implementations.
Bus 112 also connects to input and output device interfaces 122 and 116. Input device interface 122 enables the user to communicate information and select commands to the electronic system. Input devices used with input device interface 122 include, for example, alphanumeric keyboards and pointing devices (also called “cursor control devices”). Output device interfaces 116 enables, for example, the display of images generated by the electronic system 100. Output devices used with output device interface 116 include, for example, printers and display devices, such as cathode ray tubes (CRT) or liquid crystal displays (LCD). Some implementations include devices such as a touchscreen that functions as both input and output devices.
Finally, as shown in
While the above discussion primarily refers to microprocessor or multi-core processors that execute software, some implementations are performed by one or more integrated circuits, such as application specific integrated circuits (ASICs) or field programmable gate arrays (FPGAs). In some implementations, such integrated circuits execute instructions that are stored on the circuit itself.
As used in this specification and any claims of this application, the terms “computer”. “server”, “processor”, and “memory” all refer to electronic or other technological devices. These terms exclude people or groups of people. For the purposes of the specification, the terms display or displaying means displaying on an electronic device.
To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.
Embodiments of the subject matter described in this specification can be implemented in a computing system that includes a back end component, e.g., as a data server, or that includes a middleware component, e.g., an application server, or that includes a front end component, e.g., a client computer having a graphical user interface through which a user can interact with an implementation of the subject matter described in this specification, or any combination of one or more such back end, middleware, or front end components. The components of the system can be interconnected by any form or medium of digital data communication, e.g., a communication network. Examples of communication networks include a local area network (“LAN”) and a wide area network (“WAN”), an inter-network (e.g., the Internet), and peer-to-peer networks (e.g., ad hoc peer-to-peer networks).
The computing system can include clients and servers. A client and server are generally remote from each other and typically interact through a communication network. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other. Data generated at the client device (e.g., a result of the user interaction) can be received from the client device at the server.
In a conventional camera, a pixel collects the light passing through the lens from an object point outside the camera. An object P outside the camera emits or reflects the light. The light entering the lens aperture will be accumulated by the pixel.
The pixel output value is approximately proportional to the number of photons collected. When illumination is poor, the content in the scene may not be well lighted, the sensor may be unable to collect sufficient photons, and thus the content may be dark in the picture.
One way to illuminate such content is to add additional light. One possible solution is to use a flash, which adds additional light and illuminates the subject. Another is to use a reflector, which redirects some light in the scene to illuminate the subject. The reflector may be large and may not be suitable for the portable camera system like a smartphone.
Typically, a single LED flash is small in size, 3-5 mm and emits light as a spot light source. In conventional phones with multiple LED flashes, the flashes are densely packed and the total size is typically less than 8-10 mm, also leading to emission of light as a pseudo-spot light source. In the case where the phone has multiple LED flashes, these are generally designed with different colors which may simulate an environmental color temperature. The flash may still be regarded as a spot light source, because its size is typically less than 1 cm, compared to a general photo distance of 1 to 1.5 m. In both cases the spot light source is referred to as a flash unit.
E=L·ρ(ωf,ωc)·r−2·cos θ (1)
where ρ(ωf, ωc) is the surface BRDF (bidirectional reflectance distribution function), ωf and ωc are flash and view directions with respect to a local coordinate frame at P. Where r is the distance from the flash, and θ is the angle between the flash direction and the surface normal at P. This inverse square law is the reason the flash intensity falls off quickly with distance r.
From equation 1, it may be observed that, for an object with curved surface that the illumination decreases quickly with increasing distance r. The distance from the surface to the flash varies and thus different points on the main subject may not be illuminated uniformly. On a curved surface, the angle between flash direction and surface normal constantly varies, and thus the different points on the main subject may not be uniformly illuminated.
To simulate a professional photographer's capture of a portrait image with a large reflector, one possible solution is to use a flash array instead of a flash unit, to increase the uniformity of the illumination.
If equation 1 is extended to a multiple LED system, of N spot-light sources, the effect of the k-th source light on a surface point P is given by,
Ek=Lk·ρ(ωfk,ωc)·rk−2·cos θk (2)
The suffix k denotes the k-th light source. The effect of the N different spot-light sources are,
E=Σk=1NEk=Σk=1NLk·ρ(ωfk,ωc)·rk−2·cos θk (3)
If the main axis of flash unit is perpendicular to the surface, the distance between the flash and the surface is d. Then the BRDF of the planar surface with uniform diffuse reflection is set to a uniform distribution function and ρ(ωfk,ωc) is approximately a constant.
For a single flash unit the direct illumination of P by flash unit is given by
For N flash units placing on the same distance along a 1D line, with x coordinates as ui,i=1, 2, . . . N,
Multiple flash units illuminate the scene from different directions, and illuminate the scene in a wider view angle, thus improving the uniformity of the illumination area.
This two dimensional flash array extends the flash view angle along two dimensions, simulating a continuous light source on a 2D plane instead of a spot light source and thus illuminates the object more uniformly than a single flash unit.
The flash array may be used to increase the flash view angle and to make the illumination more uniform. The flash units may be aligned in directions other than orthogonal to the plane of the two dimensional plane, both horizontally and vertically.
The flash axis may be parallel to the inner normal direction as shown in
A dense Cartesian flash array is shown in
The variations discussed may be combined to achieve combined advantages. For example, there may be a sampled flash array on a curved surface, with flash units' axis converging towards an object.
The distributed array may include at least one light emitting diode where the individual LED elements may be pivotal. The individual LED elements emitting light may converge to a focal point and or emit light diffusely. The mount may have a convex or concave shape with the individual LED elements forming a plane light output and or a Fresnel reflector expressing a respective convex or concave shape with the individual LED elements forming a plane light output. The distributed array having LED elements may for rows and columns as a Cartesian flash array, an interleaved honeycomb array and or a circular array.
The mount may be slidably connected to a mobile device and or foldable. The distributed array of light emitting points may be individually deformable about two rotatable axes. The distributed array of light emitting points may include areas of optical foci and include a light gathering sheet that gathers light from a light source and distributes the light to the areas of optical foci.
Furthermore, the relative position between the camera and the flash array may be arranged in various locations on the device. In one example the camera may be mounted at the top-left corner and the flash array mounted in the middle of the cell phone back, however the camera may be mounted at various places on the back of the cell phone and the flash array may be mounted at various places on the back of the cell phone.
The fixed or liftable mounting may be contained within a cell phone case, with an additional control/charging wire linking the array to the mobile device.
Those of skill in the art would appreciate that the various illustrative blocks, modules, elements, components, methods, and algorithms described herein may be implemented as electronic hardware, computer software, or combinations of both. To illustrate this interchangeability of hardware and software, various illustrative blocks, modules, elements, components, methods, and algorithms 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. Various components and blocks may be arranged differently (e.g., arranged in a different order, or partitioned in a different way) all without departing from the scope of the subject technology.
It is understood that the specific order or hierarchy of steps in the processes disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the processes maybe rearranged. Some of the steps may be performed simultaneously. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented.
The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. The previous description provides various examples of the subject technology, and the subject technology is not limited to these examples. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the fill scope consistent with the language claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. Pronouns in the masculine (e.g., his) include the feminine and neuter gender (e.g., her and its) and vice versa. Headings and subheadings, if any, are used for convenience only and do not limit the invention. The predicate words “configured to”, “operable to”, and “programmed to” do not imply any particular tangible or intangible modification of a subject, but, rather, are intended to be used interchangeably. For example, a processor configured to monitor and control an operation or a component may also mean the processor being programmed to monitor and control the operation or the processor being operable to monitor and control the operation. Likewise, a processor configured to execute code can be construed as a processor programmed to execute code or operable to execute code.
A phrase such as an “aspect” does not imply that such aspect is essential to the subject technology or that such aspect applies to all configurations of the subject technology. A disclosure relating to an aspect may apply to all configurations, or one or more configurations. An aspect may provide one or more examples. A phrase such as an aspect may refer to one or more aspects and vice versa. A phrase such as an “embodiment” does not imply that such embodiment is essential to the subject technology or that such embodiment applies to all configurations of the subject technology. A disclosure relating to an embodiment may apply to all embodiments, or one or more embodiments. An embodiment may provide one or more examples. A phrase such as an “embodiment” may refer to one or more embodiments and vice versa. A phrase such as a “configuration” does not imply that such configuration is essential to the subject technology or that such configuration applies to all configurations of the subject technology. A disclosure relating to a configuration may apply to all configurations, or one or more configurations. A configuration may provide one or more examples. A phrase such as a “configuration” may refer to one or more configurations and vice versa.
The word “example” is used herein to mean “serving as an example or illustration.” Any aspect or design described herein as “example” is not necessarily to be construed as preferred or advantageous over other aspects or designs.
All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112, sixth paragraph, unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” Furthermore, to the extent that the term “include,” “have,” or the like is used in the description or the claims, such term is intended to be inclusive in a manner similar to the term “comprise” as “comprise” is interpreted when employed as a transitional word in a claim.
References to “one embodiment,” “an embodiment,” “some embodiments,” “various embodiments”, or the like indicate that a particular element or characteristic is included in at least one embodiment of the invention. Although the phrases may appear in various places, the phrases do not necessarily refer to the same embodiment. In conjunction with the present disclosure, those skilled in the art will be able to design and incorporate any one of the variety of mechanisms suitable for accomplishing the above described functionalities.
It is to be understood that the disclosure teaches just one example of the illustrative embodiment and that many variations of the invention can easily be devised by those skilled in the art after reading this disclosure and that the scope of then present invention is to be determined by the following claims.
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