Patent Application
20210100523
The development of consumer electronics has enabled the possibility to address the need of people's increasing awareness of their health and wellness. For example, wearable devices and smart phones have been able to host various sensor modalities for cardiovascular system monitoring, e.g., integrated electrodes for electrocardiogram (ECG), optical sensors for photoplethysmography (PPG), and pressure sensors for blood pressure. This enables people to measure parameters that can be used as an indicator for wellness themselves, for example at home without the need of a medical professional, or in the form of in-home care with the help of a medical professional. However, the ability of people to monitor their health and wellness, such as to monitor parameters of the cardiovascular system like electrical potential, pressure, or blood flow, depends on the available sensors, their ease of use, and their accuracy. Moreover, often the measurements are reflecting an averaged information over time or over (parts of) the body, lacking the details and/or fluctuations that may be useful for the monitoring process.
The accompanying drawings, which are incorporated in and form a part of the Description of Embodiments, illustrate various non-limiting and non-exhaustive embodiments of the subject matter and, together with the Description of Embodiments, serve to explain principles of the subject matter discussed below. Unless specifically noted, the drawings referred to in this Brief Description of Drawings should be understood as not being drawn to scale and like reference numerals refer to like parts throughout the various figures unless otherwise specified.
The following Description of Embodiments is merely provided by way of example and not of limitation. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding background or in the following Description of Embodiments.
Reference will now be made in detail to various embodiments of the subject matter, examples of which are illustrated in the accompanying drawings. While various embodiments are discussed herein, it will be understood that they are not intended to limit to these embodiments. On the contrary, the presented embodiments are intended to cover alternatives, modifications and equivalents, which may be included within the spirit and scope the various embodiments as defined by the appended claims. Furthermore, in this Description of Embodiments, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the present subject matter. However, embodiments may be practiced without these specific details. In other instances, well known methods, procedures, components, and circuits have not been described in detail as not to unnecessarily obscure aspects of the described embodiments.
Some portions of the detailed descriptions which follow are presented in terms of procedures, logic blocks, processing and other symbolic representations of operations on data within an electrical device. These descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. In the present application, a procedure, logic block, process, or the like, is conceived to be one or more self-consistent procedures or instructions leading to a desired result. The procedures are those requiring physical manipulations of physical quantities. Usually, although not necessarily, these quantities take the form of acoustic (e.g., ultrasonic) signals capable of being transmitted and received by an electronic device and/or electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated in an electrical device.
It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the following discussions, it is appreciated that throughout the description of embodiments, discussions utilizing terms such as “performing,” “determining,” “detecting,” “integrating,” “calculating,” “correcting,” “providing,” “receiving,” “analyzing,” “confirming,” “displaying,” “presenting,” “using,” “completing,” “instructing,” “comparing,” “executing,” or the like, refer to the actions and processes of an electronic device such as an electrical device.
Embodiments described herein may be discussed in the general context of processor-executable instructions residing on some form of non-transitory processor-readable medium, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or distributed as desired in various embodiments.
In the figures, a single block may be described as performing a function or functions; however, in actual practice, the function or functions performed by that block may be performed in a single component or across multiple components, and/or may be performed using hardware, using software, or using a combination of hardware and software. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, logic, circuits, and steps have been described 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 disclosure. Also, the example ultrasonic sensing system and/or mobile electronic device described herein may include components other than those shown, including well-known components.
Various techniques described herein may be implemented in hardware, software, firmware, or any combination thereof, unless specifically described as being implemented in a specific manner. Any features described as modules or components may also 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 non-transitory processor-readable storage medium comprising instructions that, when executed, perform one or more of the methods described herein. The non-transitory processor-readable data storage medium may form part of a computer program product, which may include packaging materials.
The non-transitory processor-readable storage medium may comprise 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, other known storage media, and the like. The techniques additionally, or alternatively, may be realized at least in part by a processor-readable communication medium that carries or communicates code in the form of instructions or data structures and that can be accessed, read, and/or executed by a computer or other processor.
Various embodiments described herein may be executed by one or more processors, such as one or more motion processing units (MPUs), sensor processing units (SPUs), host processor(s) or core(s) thereof, digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), application specific instruction set processors (ASIPs), field programmable gate arrays (FPGAs), a programmable logic controller (PLC), a complex programmable logic device (CPLD), a discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein, or other equivalent integrated or discrete logic circuitry. The term “processor,” as used herein may refer to any of the foregoing structures or any other structure suitable for implementation of the techniques described herein. As it employed in the subject specification, the term “processor” can refer to substantially any computing processing unit or device comprising, but not limited to comprising, single-core processors; single-processors with software multithread execution capability; multi-core processors; multi-core processors with software multithread execution capability; multi-core processors with hardware multithread technology; parallel platforms; and parallel platforms with distributed shared memory. Moreover, processors can exploit nano-scale architectures such as, but not limited to, molecular and quantum-dot based transistors, switches and gates, in order to optimize space usage or enhance performance of user equipment. A processor may also be implemented as a combination of computing processing units.
In addition, in some aspects, the functionality described herein may be provided within dedicated software modules or hardware modules configured as described herein. Also, the techniques could be fully implemented in one or more circuits or logic elements. 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 an SPU/MPU and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with an SPU core, MPU core, or any other such configuration.
Discussion begins with a description of an example system for determining blood vessel characteristic change using an ultrasonic sensor. Example operations of a system for determining blood vessel characteristic change using an ultrasonic sensor are then described.
Medical ultrasound technology is currently employed by medical professional for imaging of the vascular system. Based on the images, medical professionals, such as ultrasound technicians, can deduce various forms of information regarding vascular health, such as vascular wall motion tracking, blood flow, or elastic properties of the soft tissues (e.g., elastography). Typical ultrasound systems currently in use are for clinical usage and meant to be operated by specially educated medical experts. Conventional medical ultrasonic systems typically include ultrasound probes with various shapes and form factors for different body parts, and often output images that are then analyzed further. In a clinical setting, the ultrasound system is used by a physician or clinician to align the probes to the physiological sites of interest and diagnose based on the static ultrasound imaging, Doppler imaging, and elastography. Due to the complexity of the biological system and usage of the ultrasound systems, extensive ultrasound imaging and medical training is needed for ultrasound examination and diagnosis.
Technology development over the last decades has resulted in miniaturized ultrasonic transducers as well as ever-increasing data processing power and storage. An example of the currently available miniaturized ultrasonic transducers is the application of ultrasonic fingerprint sensors in mobile devices. Embodiments describe herein provide a miniaturized ultrasonic sensor system for cardiovascular system monitoring. The described system provides a user friendly system that does not necessarily require operation by a trained medical professional, but due to system optimization and signal processing, allows for home usage. For example, the described system can be used by people at home (without medical training), by in-home care personnel, or even by automated home robots or similar autonomous devices. The system can measure and output various parameters of the blood vessels, e.g., blood vessel diameter and time variations, pulse wave velocity, blood pressure, etc. The described system may also output a wellness indicator based on these parameters, and this wellness indicator may be monitored over time.
Embodiments described herein provide a method for determining blood vessel characteristic change using an ultrasonic sensor. A plurality of ultrasonic signal transmit and receive operations is performed at a position overlying a blood vessel of a person using an ultrasonic sensor, wherein the plurality of ultrasonic signal transmit and receive operations generate a plurality of received signals. Depths of blood vessel walls of one blood vessel (e.g., a closer blood vessel wall and a farther blood vessel wall relative to the ultrasonic sensor) are automatically determined at the position for a plurality of time instances based on local maxima of a combination of an acoustic impedance mismatch and a motion characteristic based at least in part on the plurality of received signals. A change in a blood vessel characteristic is determined based at least in part on a difference between the depths of the blood vessel walls at the plurality of time instances. In one embodiment, the blood vessel characteristic is a diameter change of the blood vessel. In another embodiment, the blood vessel characteristic is a blood pressure. In another embodiment, the blood vessel characteristic is a pulse wave velocity of the blood vessel.
In some embodiments, where the motion characteristic is a velocity of tissue, determination of the depths of blood vessel walls includes determining the velocity of the tissue using at least a phase of the received signals. In one embodiment, determination of the velocity of the tissue at the plurality of time instances includes performing Doppler signal processing on the plurality of received signals to determine the velocity of the tissue at the plurality of time instances.
In some embodiments, determination of the depths of blood vessel walls at the position for a plurality of time instances includes determining a weighted velocity of the tissue at the plurality of time instances based on signal amplitudes (e.g., due to an acoustic impedance mismatch) of the plurality of received signals at the plurality of time instances and the velocity of the tissue at the plurality of time instances. In one embodiment, the weighted velocity of the tissue depends on an impact of the acoustic impedance mismatch and on the velocity of the tissue.
In some embodiments, determination of the depths of blood vessel walls at the position for a plurality of time instances based at least in part on the plurality of received signals includes detecting at least one local maximum of the combination of the acoustic impedance mismatch and the motion characteristic based at least in part on the plurality of received signals, wherein the at least one local maximum corresponds to one blood vessel wall. In some embodiment, two local maxima are detected, where one local maximum corresponds to a closer wall of the blood vessel relative to the ultrasonic sensor and the other local maximum corresponds to a farther wall of the blood vessel relative to the ultrasonic sensor. In another embodiment, determination of the depths of blood vessel walls at the position for a plurality of time instances based at least in part on the plurality of received signals includes determining two depth ranges for the blood vessel based on blood vessel geometry, where a first depth range comprises a closer wall of the blood vessel relative to the ultrasonic sensor and a second depth range comprises a farther wall of the blood vessel relative to the ultrasonic sensor. A first local maximum weighted velocity within the first depth range is determined, wherein the first local maximum weighted velocity within the first depth range corresponds to the depth of the closer wall of the blood vessel, and a second local maximum weighted velocity within the second depth range is determined, wherein the second local maximum weighted velocity within the second depth range corresponds to the depth of the farther wall of the blood vessel. In one embodiment, the blood vessel characteristic is a change in blood vessel diameter.
In some embodiments, determination of a change in a blood vessel characteristic based at least in part on a difference between the depths of the blood vessel walls at the plurality of time instances includes determining a velocity of the blood vessel at the depth of the closer wall and a velocity of the blood vessel at the depth of the farther wall at the plurality of time instances, where the velocity of the blood vessel at the depth of the closer wall and the velocity of the blood vessel at the depth of the farther wall are out of phase. The velocity of the blood vessel at the depth of the closer wall and the velocity of the blood vessel at the depth of the farther wall being out of phase can be used as validation that a blood vessel has correctly been found. The velocity of the blood vessel at the depth of the closer wall and the velocity of the blood vessel at the depth of the farther wall is integrated to generate a displacement of the closer wall and a displacement of the farther wall. A change in diameter of the blood vessel is calculated at the plurality of time instances based on a difference of the displacement of the closer wall and the displacement of the farther wall. In addition, by using the time-of-flight (TOF) between the vessel walls to determine the absolute diameter of the blood vessel, the variation in the absolute blood vessel diameter can be determined over time. Moreover, if an additional pressure sensor can obtain pressure at the same location, vascular distensibility and compliance can be derived from pressure and volume change.
In some embodiments, the motion characteristic at tissue at a depth between the ultrasonic sensor and a closer blood vessel wall relative to the ultrasonic sensor is determined. Motion artifacts within displacement of the blood vessel walls are corrected for by using the motion characteristic at tissue at a depth between the ultrasonic sensor and a closer blood vessel wall relative to the ultrasonic sensor.
As a heart pumps the blood through the vascular system, a pressure wave runs along the blood vessels, which themselves are elastic and flexible. This pressure wave causes the elastic vessels to expand and contract as these pressure waves pass. As a result, there is an expansion wave running along the blood vessels with each heartbeat, where this pressure wave is referred to as the pulse. The pulse wave velocity (PWV) is the velocity at which the blood pressure wave propagates through the circulatory system. As is known by persons skilled in the art, the blood pressure can be calculated from diameter change with some calibration or assumption of the blood vessel geometry (e.g. shape and thickness of the vessel walls) and material properties (e.g. arterial stiffness). The arterial stiffness depends on the pressure, but may be considered a constant as a first order approximation. Under this assumption, there is a linear relationship between the blood pressure and the diameter change of the blood vessel. To determine the parameters of this linear relationship (i.e. slope and bias), a calibration of the system is required, for example by determining the diastolic and systolic pressure, using e.g. a blood pressure cuff. Instead of assuming the arterial stiffness as a constant, the PWV can be used to determine the blood pressure and take into consideration the dependence of the arterial stiffness on the pressure. In this case, the blood pressure is a function of the PWV and the diameter change of the blood vessel. Using the PWV, the absolute pressure change, from diastolic to systolic pressure, can be determined without any calibration. However, the baseline pressure can then be added using a single pressure calibration. This disclosure provides example embodiments of automatic determination of the blood vessel wall diameter change of time and of the pulse wave velocity. Other blood vessel characteristics can then be determined based on these determinations, such as blood pressure, vascular distensibility, vascular compliance, and many others.
As discussed above, in conventional medical ultrasonic imaging, first an image or plurality of images of the blood vessel would be captured, and then the required information is deduced from the image (sequence). In the described sensing system, the blood vessel 110 and blood flow characteristics are measured in a more direct method, automatically, without an intermediate imaging process, and without the requirement of a technician. The sensor transmits ultrasonic waves which are reflected at any boundaries in the tissue that have an acoustic impedance mismatch, e.g., the boundaries and walls of the blood vessels. The reflected signal also comes from ultrasound waves reflected inside the tissue through various scattering mechanisms, and the reflected signals are therefore not only from blood vessels. The reflected ultrasound waves are then measured by the sensor. The Time-Of-Flight (TOF) of the signal is an indication of the depth of the feature the signal reflected off. Using the received signals, blood vessel wall velocity caused by blood flow in a flexible blood vessel can be determined, allowing for the determination of various blood vessel characteristics, such as blood pressure (as illustrated by the Systolic pressure and the Diastolic pressure), blood vessel diameter change, and pulse wave velocity.
Ultrasonic signals are received at signal receiver 410. It should be appreciated that, in accordance with various embodiments, signal receiver 410 is an ultrasonic sensor (e.g., a sensor capable of transmitting and receiving ultrasonic signals) or coupled to an ultrasonic sensor. The ultrasonic sensor is operable to emit and detect ultrasonic waves (also referred to as ultrasonic signals or ultrasound signals). One or more ultrasonic transducers (e.g., Piezoelectric Micromachined Ultrasonic Transducers (PMUTs)), which may be comprised within an array configured to determine blood vessel measurement, may be used to transmit and receive the ultrasonic waves, where the ultrasonic transducers are capable of performing both the transmission and receipt of the ultrasonic waves. The emitted ultrasonic waves are reflected from any objects in contact with (or in front of) the ultrasonic sensor, and can project into the object at various depths, and these reflected ultrasonic waves, or echoes, are then detected. Where the object is a human body (e.g., at an arm or a wrist), the waves are projected into the tissue of the human body, and reflect at different tissue depths due to acoustic impedance mismatches.
Signal receiver 410 communicates signals 415 to automatic vessel wall location determination 420 which is configured to automatically determine depths of blood vessel walls at the position for a plurality of time instances based on local maxima of a combination of an acoustic impedance mismatch and a motion characteristic based at least in part on the received signals 415. An acoustic impedance mismatch happens at boundaries between materials having different acoustic properties, e.g., blood vessel walls and blood flowing in the blood vessel or the tissue around the blood vessels. In some embodiments, the motion characteristic is the velocity of the blood vessel walls as it expands and contracts, e.g., the velocity of the blood vessel walls moving away from and towards the ultrasonic sensor positioned on the body.
With reference to
The automatic detection of the location of the blood vessel is based on a combination of the following insights: 1) the blood vessel walls have a distinct acoustic impedance mismatch with the surrounding blood and tissue, and 2) the vessel walls move in a direction perpendicular to the blood flow. The described system takes advantage of these properties to automatically locate the blood vessel because the vessel walls have the highest combined impedance mismatch and tissue velocity (in the required direction). One example method to use a parameter to express the combined impedance mismatch and tissue velocity, is to introduce a weighted tissue velocity, where the weight is based on the impedance mismatch (e.g., the reflected signal intensity). The location of blood vessel walls is based on both an acoustic impedance mismatch, as indicated in signal 415, and the velocity of the tissue. With reference to
With reference to
With reference to
In some embodiments, local maxima determination 470 includes depth range determination 472 which is configured to determine two depth ranges for the blood vessel based on blood vessel geometry. While the location and geometry of blood vessels can vary from person to person, it is possible to determine two depth ranges, where a first depth range includes a closer wall of the blood vessel relative to the ultrasonic sensor and a second depth range includes a farther wall of the blood vessel relative to the ultrasonic sensor. A first local maximum weighted velocity is determined within the first depth range, where the first local maximum weighted velocity within the first depth range corresponds to the depth of the closer wall of the blood vessel, and second local maximum weighted velocity is determined within the second depth range, where the second local maximum weighted velocity within the second depth range corresponds to the depth of the farther wall of the blood vessel. In some embodiments, the first depth range and second depth range can be determined during a calibration phase, and can be used for location verification using the approximate distance between the maxima.
Graph 730 illustrates the weighted velocity (e.g., graph 632). Using first depth range 720 and second depth range 722, where the first depth range corresponds to 50-100 on the Fast Time Index and the second depth range corresponds to 125-175 on the Fast Time Index, two maximum velocities 732 and 734 can be determined, wherein each maximum weighted velocity is associated with a depth location of the corresponding blood vessel wall. Graphs 740 and 742 illustrate the velocity profiles at the two local maxima indicated in graph 730. In embodiments without predefined depth ranges, the local maxima in the weighted velocity graph can be used to find the blood vessel walls. A sliding windows may be used to find the local maxima, where the windows size is related to the (approximate) size of the blood vessel. As discussed above, additional criteria can be used to verify that the candidate locations of the blood vessel walls corresponding to the local maxima are indeed the walls of the blood vessel. Graph 730 shows how to use the weighted velocity to determine the vessel diameter (change). This can be done at a plurality of lateral locations to determine the center location and/or vessel geometry. Furthermore, a similar strategy as discussed to determine the vessel diameter can be used to determine the vessel wall thickness. In this case, the first impedance mismatch is between the tissue and the blood vessel wall, and the second impedance mismatch is between the vessel wall and the blood in the vessel. This would then again lead to two local maxima in the weighted velocity plots, where the distance between the maxima is a measure for the vessel wall thickness. Because of the smaller dimension of the vessel wall thickness compared to the vessel wall diameter, a higher resolution and accuracy (e.g., SNR) is required.
With reference to
With reference to
Based on the ultrasound measurements, different characteristics of the blood vessel and blood flow can be determined. Furthermore, by monitoring the characteristics over time changes in the characteristics or wellness of the user may be determined. The data and results of the sensor may also be combined with results from other sensors such as an ECG or PPG. The data of the sensor may also be linked to the context and/or activities of the user to monitor the wellness of the user in relation to the context and/or activities. The wellness device containing the sensor may also include other sensors, e.g., motion sensors, for determine the context and/or activity.
In some embodiments, blood vessel characteristic change determination 430 is configured to determine a blood pressure using vessel wall displacement 425. In some embodiments, blood vessel characteristic change determination 430 is configured to determine a diameter change of the blood vessel using vessel wall displacement 425.
With reference to
In some instances, the motion artifacts may be so severe that the diameter calculation does not naturally reduce or cancel out the motion artifacts. In some embodiments, a motion characteristic (e.g., velocity) is determined at tissue outside the blood vessel and used to correct for motion artifacts. For example, the velocity within a stationary layer of tissue between the blood vessel and the ultrasonic sensor can be determined. Since this stationary layer is not, or less, influenced by the vessel motion, and detected motion is linked to external motion that can cause motion artifacts, the determined motion at the stationary layer can then be used to correct the determined vessel wall motion for any motion artifacts due to external motion.
For each of the configurations illustrated in
The array of transducers may be used for forming and steering an ultrasonic beam. The beam forming can be used to focus the ultrasonic waves at the correct depth, and the beam steering may be used to control lateral motion of the beam to find the blood vessel. For example, when the sensor is placed on the skin, the sensor may not be exactly above the blood vessel. The beam steering and beamforming may be used to find the vessel in a first step through a scanning action, and once the vessel is located, in a second step perform the blood vessel and blood flow measurements. The beam forming and beam steering can be accomplished by applying small phase delays to the individual transducers. The PMUTs may be controlled individually, or the PMUTs may be grouped together in subsets of PMUTs. These subset of pixels may be connected together. For example,
In some embodiments, the wellness devices may include additional sensors and/or actuators that work together with the ultrasonic sensor. For example, in a system like a blood pressure cuff, actuators may be used to press or inflate the cuffs, and a pressure sensor may be present for monitoring this process. The system may control the sensor based on the actuator or pressure sensor readings (or vice-versa). As a result, the sensor may provide cardiovascular data as a function of the applied pressure. The principle of applying different pressures or forces may also enable characterization that would not be possible at a static situation. Other combinations of sensors and actuators are also envisioned for various applications.
Turning now to the figures,
As depicted in
Host processor 1210 can be one or more microprocessors, central processing units (CPUs), DSPs, general purpose microprocessors, ASICs, ASIPs, FPGAs or other processors which run software programs or applications, which may be stored in host memory 1230, associated with the functions and capabilities of wellness sensing device 1200.
Host bus 1220 may be any suitable bus or interface to include, without limitation, a peripheral component interconnect express (PCIe) bus, a universal serial bus (USB), a universal asynchronous receiver/transmitter (UART) serial bus, a suitable advanced microcontroller bus architecture (AMBA) interface, an Inter-Integrated Circuit (I2C) bus, a serial digital input output (SDIO) bus, a serial peripheral interface (SPI) or other equivalent. In the embodiment shown, host processor 1210, host memory 1230, display 1240, interface 1250, transceiver 1260, sensor processing unit (SPU) 1270, and other components of wellness sensing device 1200 may be coupled communicatively through host bus 1220 in order to exchange commands and data. Depending on the architecture, different bus configurations may be employed as desired. For example, additional buses may be used to couple the various components of wellness sensing device 1200, such as by using a dedicated bus between host processor 1210 and memory 1230.
Host memory 1230 can be any suitable type of memory, including but not limited to electronic memory (e.g., read only memory (ROM), random access memory, or other electronic memory), hard disk, optical disk, or some combination thereof. Multiple layers of software can be stored in host memory 1230 for use with/operation upon host processor 1210. For example, an operating system layer can be provided for wellness sensing device 1200 to control and manage system resources in real time, enable functions of application software and other layers, and interface application programs with other software and functions of wellness sensing device 1200. Similarly, a user experience system layer may operate upon or be facilitated by the operating system. The user experience system may comprise one or more software application programs such as menu navigation software, games, device function control, gesture recognition, image processing or adjusting, voice recognition, navigation software, communications software (such as telephony or wireless local area network (WLAN) software), and/or any of a wide variety of other software and functional interfaces for interaction with the user can be provided. In some embodiments, multiple different applications can be provided on a single wellness sensing device 1200, and in some of those embodiments, multiple applications can run simultaneously as part of the user experience system. In some embodiments, the user experience system, operating system, and/or the host processor 1210 may operate in a low-power mode (e.g., a sleep mode) where very few instructions are processed. Such a low-power mode may utilize only a small fraction of the processing power of a full-power mode (e.g., an awake mode) of the host processor 1210.
Display 1240, when included, may be a liquid crystal device, (organic) light emitting diode device, or other display device suitable for creating and visibly depicting graphic images and/or alphanumeric characters recognizable to a user. Display 1240 may be configured to output images viewable by the user and may additionally or alternatively function as a viewfinder for camera. It should be appreciated that display 1240 is optional, as various electronic devices, such as electronic locks, doorknobs, car start buttons, etc., may not require a display device.
Interface 1250, when included, can be any of a variety of different devices providing input and/or output to a user, such as audio speakers, touch screen, real or virtual buttons, joystick, slider, knob, printer, scanner, computer network I/O device, other connected peripherals and the like.
Transceiver 1260, when included, may be one or more of a wired or wireless transceiver which facilitates receipt of data at wellness sensing device 1200 from an external transmission source and transmission of data from wellness sensing device 1200 to an external recipient. By way of example, and not of limitation, in various embodiments, transceiver 1260 comprises one or more of: a cellular transceiver, a wireless local area network transceiver (e.g., a transceiver compliant with one or more Institute of Electrical and Electronics Engineers (IEEE) 802.11 specifications for wireless local area network communication), a wireless personal area network transceiver (e.g., a transceiver compliant with one or more IEEE 802.15 specifications for wireless personal area network communication), and a wired a serial transceiver (e.g., a universal serial bus for wired communication).
Wellness sensing device 1200 also includes a general purpose sensor assembly in the form of integrated Sensor Processing Unit (SPU) 1270 which includes sensor processor 1272, memory 1276, a ultrasonic sensor 1278, and a bus 1274 for facilitating communication between these and other components of SPU 1270. In some embodiments, SPU 1270 may include at least one additional sensor 1280 (shown as sensor 1280-1, 1280-2, . . . 1280-n) communicatively coupled to bus 1274. In some embodiments, at least one additional sensor 1280 is a force or pressure sensor (e.g. a touch sensor) configured to determine a force or pressure or a temperature sensor configured to determine a temperature at wellness sensing device 1200. The force or pressure sensor may be disposed within, under, or adjacent ultrasonic sensor 1278. In some embodiments, all of the components illustrated in SPU 1270 may be embodied on a single integrated circuit. It should be appreciated that SPU 1270 may be manufactured as a stand-alone unit (e.g., an integrated circuit), that may exist separately from a larger electronic device and is coupled to host bus 1220 through an interface (not shown). It should be appreciated that, in accordance with some embodiments, that SPU 1270 can operate independent of host processor 1210 and host memory 1230 using sensor processor 1272 and memory 1276.
Sensor processor 1272 can be one or more microprocessors, CPUs, DSPs, general purpose microprocessors, ASICs, ASIPs, FPGAs or other processors which run software programs, which may be stored in memory 1276, associated with the functions of SPU 1270. It should also be appreciated that ultrasonic sensor 1278 and additional sensor 1280, when included, may also utilize processing and memory provided by other components of wellness sensing device 1200, e.g., host processor 1210 and host memory 1230.
Bus 1274 may be any suitable bus or interface to include, without limitation, a peripheral component interconnect express (PCIe) bus, a universal serial bus (USB), a universal asynchronous receiver/transmitter (UART) serial bus, a suitable advanced microcontroller bus architecture (AMBA) interface, an Inter-Integrated Circuit (I2C) bus, a serial digital input output (SDIO) bus, a serial peripheral interface (SPI) or other equivalent. Depending on the architecture, different bus configurations may be employed as desired. In the embodiment shown, sensor processor 1272, memory 1276, ultrasonic sensor 1278, and other components of SPU 1270 may be communicatively coupled through bus 1274 in order to exchange data.
Memory 1276 can be any suitable type of memory, including but not limited to electronic memory (e.g., read only memory (ROM), random access memory, or other electronic memory). Memory 1276 may store algorithms or routines or other instructions for processing data received from ultrasonic sensor 1278 and/or one or more sensor 1280, as well as the received data either in its raw form or after some processing. Such algorithms and routines may be implemented by sensor processor 1272 and/or by logic or processing capabilities included in ultrasonic sensor 1278 and/or sensor 1280.
A sensor 1280 may comprise, without limitation: a temperature sensor, a humidity sensor, an atmospheric pressure sensor, an infrared sensor, a radio frequency sensor, a navigation satellite system sensor (such as a global positioning system receiver), an acoustic sensor (e.g., a microphone), an inertial or motion sensor (e.g., a gyroscope, accelerometer, or magnetometer) for measuring the orientation or motion of the sensor in space, or other type of sensor for measuring other physical or environmental factors. In one example, sensor 1280-1 may comprise an acoustic sensor, sensor 1280-2 may comprise a temperature sensor, and sensor 1280-n may comprise a motion sensor.
In some embodiments, ultrasonic sensor 1278 and/or one or more sensors 1280 may be implemented using a microelectromechanical system (MEMS) that is integrated with sensor processor 1272 and one or more other components of SPU 1270 in a single chip or package. Although depicted as being included within SPU 1270, one, some, or all of ultrasonic sensor 1278 and/or one or more sensors 1280 may be disposed externally to SPU 1270 in various embodiments.
The ultrasonic sensor 1278 may be used to obtain blood vessel and blood flow characteristics, and the ultrasonic sensor 1278 or SPU 1270 may transfer this data to the host device. The host processor 1210 may then convert the data into a wellness indicator, or may present the data to the user. The host device may contain different wellness sensors for measuring different health indicators. These sensors may be based on ultrasonic sensors, or other type of sensors (e.g., sensors 1280). The ultrasonic sensor 1278 may perform different types of characterizations, for example in different modes. In the discussion above, the focus was on blood flow measurements, but other measurements may be performed. For example, the ultrasonic sensor 1278 may measure tissue characteristics based on the reflected ultrasound waves and use that information to derive a health indicator.
With reference to
At procedure 1320, depths of blood vessel walls (e.g., a closer blood vessel wall and a farther blood vessel wall relative to the ultrasonic sensor) are automatically determined at the position for a plurality of time instances based on local maxima of a combination of an acoustic impedance mismatch and a motion characteristic based at least in part on the plurality of received signals.
In some embodiments, procedure 1320 is performed according to the procedures of flow diagram 1400 of
At procedure 1420, a weighted velocity of the tissue at the plurality of time instances is determined based on signal amplitudes of the plurality of received signals at the plurality of time instances and the velocity of the tissue at the plurality of time instances. In one embodiment, the weighted velocity of the tissue depends on an impact of the acoustic impedance mismatch on the velocity of the tissue.
At procedure 1430, two local maxima of the combination of the acoustic impedance mismatch and the motion characteristic are determined based at least in part on the plurality of received signals, wherein the two local maxima correspond to the blood vessel walls. In some embodiments, as shown at procedure 1432, two depth ranges for the blood vessel based are determined on blood vessel geometry, where a first depth range comprises a closer wall of the blood vessel relative to the ultrasonic sensor and a second depth range comprises a farther wall of the blood vessel relative to the ultrasonic sensor. At procedure 1434, a first local maximum weighted velocity within the first depth range is determined, wherein the first local maximum weighted velocity within the first depth range corresponds to the depth of the closer wall of the blood vessel. At procedure 1436, a second local maximum weighted velocity within the second depth range is determined, wherein the second local maximum weighted velocity within the second depth range corresponds to the depth of the farther wall of the blood vessel. In one embodiment, the blood vessel characteristic is a change in blood vessel diameter.
At procedure 1440, a velocity of the blood vessel at the depth of the closer wall and a velocity of the blood vessel at the depth of the farther wall at the is determined plurality of time instances, where the velocity of the blood vessel at the depth of the closer wall and the velocity of the blood vessel at the depth of the farther wall are out of phase. At procedure 1450, the velocity of the blood vessel at the depth of the closer wall and the velocity of the blood vessel at the depth of the farther wall is integrated to generate a displacement of the closer wall and a displacement of the farther wall.
With reference to
At procedure 1350, a change in a blood vessel characteristic is determined based at least in part on a difference between the depths of the blood vessel walls at the plurality of time instances. In one embodiment, as shown at procedure 1352, a diameter of the blood vessel is calculated at the plurality of time instances based on a difference of the displacement of the closer wall and the displacement of the farther wall. In one embodiment, the blood vessel characteristic is a blood pressure. In another embodiment, the blood vessel characteristic is a pulse wave velocity of the blood vessel.
The examples set forth herein were presented in order to best explain, to describe particular applications, and to thereby enable those skilled in the art to make and use embodiments of the described examples. However, those skilled in the art will recognize that the foregoing description and examples have been presented for the purposes of illustration and example only. Many aspects of the different example embodiments that are described above can be combined into new embodiments. The description as set forth is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
Reference throughout this document to “one embodiment,” “certain embodiments,” “an embodiment,” “various embodiments,” “some embodiments,” or similar term means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of such phrases in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any embodiment may be combined in any suitable manner with one or more other features, structures, or characteristics of one or more other embodiments without limitation.
This application claims also priority to and the benefit of co-pending U.S. Provisional Patent Application 62/911,083, filed on Oct. 4, 2019, entitled “ULTRASONIC WELLNESS SENSOR,” by Xiaoyue Jiang, having Attorney Docket No. IVS-934-PR, and assigned to the assignee of the present application, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62911083 | Oct 2019 | US |
