Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
  • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
  • G06V40/16—Human faces, e.g. facial parts, sketches or expressions
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V10/00—Arrangements for image or video recognition or understanding
  • G06V10/20—Image preprocessing
  • G06V10/36—Applying a local operator, i.e. means to operate on image points situated in the vicinity of a given point; Non-linear local filtering operations, e.g. median filtering
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V10/00—Arrangements for image or video recognition or understanding
  • G06V10/40—Extraction of image or video features
  • G06V10/50—Extraction of image or video features by performing operations within image blocks; by using histograms, e.g. histogram of oriented gradients [HoG]; by summing image-intensity values; Projection analysis
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V10/00—Arrangements for image or video recognition or understanding
  • G06V10/94—Hardware or software architectures specially adapted for image or video understanding
  • G06V10/955—Hardware or software architectures specially adapted for image or video understanding using specific electronic processors
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V40/00—Recognition of biometric, human-related or animal-related patterns in image or video data
  • G06V40/10—Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
  • G06V40/107—Static hand or arm
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V20/00—Scenes; Scene-specific elements
  • G06V20/40—Scenes; Scene-specific elements in video content
  • G06V20/44—Event detection

Definitions

• Many devices offer scant functionality due to the fact that they must operate in a limited-power environment, such as one that relies of battery power. Examples of such devices abound, and they include categories such as toys, Internet of Things (IoT) devices, and the like.
• IoT Internet of Things
• a toy may be battery-operated and may not be readily recharged on a regular basis and may have limited or no capability to be recharged. While limiting the functionality of such devices to a bare minimum does extend battery life, such a crude approach often results in inferior performance and lackluster user experience.
• Such an apparatus may comprise dedicated computer vision (CV) computation hardware configured to receive sensor data from a sensor array comprising a plurality of sensor pixels and capable of computing one or more CV features using readings from neighboring sensor pixels of the sensor array.
• the apparatus may further comprise a first processing unit configured to control operation of the dedicated CV computation hardware.
• the first processing unit may be further configured to execute one or more application programs and, in conjunction with execution of the one or more application programs, communicate with at least one input/output (I/O) device controller, to effectuate an I/O operation in reaction to an event generated based on operations performed on the one or more computed CV features.
• I/O input/output
• the apparatus may further comprise a classifier configured to receive an output of the dedicated CV computation hardware and perform the operations based on the one or more computed CV features.
• the event may be generated in response to an output of the classifier.
• the event is a face-detection event.
• the dedicated CV computation hardware may be configured to provide an indication of the event to the first processing unit, in response to polling by the first processing unit.
• the event is generated by the first processing unit.
• the first processing unit may be configured to control operation of the dedicated CV computation hardware by specifying parameters associated with and affecting the computation of the one or more CV features.
• the first processing unit comprises a core and a second core.
• the first core may be configured to control the operation of the dedicated CV computation hardware.
• the second core may be configured to execute the one or more application programs.
• the first processing unit comprises a software environment.
• the software environment may support the one or more application programs.
• the I/O device controller comprises a media device controller.
• the media device controller may be configured to generate an audio output, a visual output, or the like.
• the I/O device controller comprises a proportional-integral-derivative (PID) controller.
• PID controller may be configured to generate a control signal to adjust a movable member to a desired position.
• FIG. 1 illustrates an example setup in which a user may be interacting with a mobile device that incorporates the features and techniques described herein
• FIG. 2A is a block diagram of a configuration including a sensor system and main processor, according to one embodiment.
• FIG. 2B is a block diagram of a sensor system with a sensor array unit, microprocessor, and example peripheral circuitry 214, according to one embodiment.
• FIGS. 3A-3C are block diagrams illustrating how components of a sensor system can be utilized to provide low-power sensor processing, according to some embodiments.
• FIG. 4 is a flow diagram of a method of sensing dynamic scene-based occurrences, according to an embodiment.
• FIG. 5 is a simplified illustration of an example sensor array.
• FIG. 6 is a simplified illustration of an example configurations of the sensor array of FIG. 5.
• FIGS. 7-9 are flow diagrams illustrating example methods for using a sensor system for computer vision computations and lower-power optical sensor readings.
• FIGS. 10A-10B are state diagrams illustrating example states of a sensor system for computer vision computations and lower-power optical sensor readings.
• FIGS. 11 A-l 1C illustrate a process of converting the sensor readings from a plurality of sensor elements to CV features, according to some embodiments.
• FIG. 12 depicts an application environment for deploying a low-power, single- processor system for handling computer vision hardware control and application program execution, according to an embodiment of the present disclosure.
• FIG. 13 A is a block diagram of components in a low-power, single-processor system utilizing multiple software components for handling computer vision hardware control and application program execution, according to an embodiment of the disclosure.
• FIG. 13B is a block diagram of components in a single-processor system utilizing multiple hardware cores for handling computer vision hardware control and application program execution, according to an embodiment of the disclosure.
• FIG. 14 shows an example of a limited search area specified to streamline feature detection, according to certain embodiments.
• FIG. 15 shows one example of an I/O device, i.e., an actuator, that may be operated in response to an event detected based on CV operations.
• an I/O device i.e., an actuator
• FIG. 16A shows an example of a toy doll that may be installed with a pair of mechanically-adjustable eyes operated based on face-detection.
• FIG. 16B shows an example of a door that opens automatically based on face- detection.
• FIG. 16C shows yet another example, one of a toy robot that is capable of interacting with a user based on face-detection.
• FIG. 17 is flow chart illustrating a process for reacting to scene-based occurrences.
• FIG. 18 is a block diagram of internal components of a mobile device that can utilize the techniques and features described herein, according to an embodiment.
• FIG. 1 illustrates an example setup 100 in which a user 130 may be interacting with a mobile device 105 that incorporates the features and techniques described herein.
• the user 130 may interact with the mobile device 105, at least in part, via a sensor system having a special-purpose camera, dedicated computer vision (CV) computation hardware, and a dedicated low-power microprocessor as described herein below.
• CV computer vision
• FIG. 1 illustrates an example setup 100 in which a user 130 may be interacting with a mobile device 105 that incorporates the features and techniques described herein.
• the user 130 may interact with the mobile device 105, at least in part, via a sensor system having a special-purpose camera, dedicated computer vision (CV) computation hardware, and a dedicated low-power microprocessor as described herein below.
• CV computer vision
• the sensor system processes the information retrieved from the camera using the included embedded processor and sends "events" (or indications that one or more reference occurrences have occurred) for the main processor only when needed or as defined and configured by the application.
• the sensor system may initiate the action by generating and sending a signal representing the "event" to the main processor, when a feature is detected. The sensor system may do so without any prompting by the main processor.
• the main processor may poll the sensor system (e.g., periodically, on an as-needed basis, etc.), and the sensor system may respond to the polling with an indication of whether or not a feature has been detected. The response to the polling may constitute the "event” in such embodiments.
• microprocessor which is typically relatively high-speed and high-power to support a variety of applications
• a low-power e.g., sleep mode
• a smart sensor capable of performing object detection, recognition, etc., can be useful in a variety of applications including internet of things (IoT) applications.
• IoT internet of things
• the dedicated CV computation hardware computes or is capable of computing CV features, or localized CV features for each sensor element or pixel in a sensor array unit, based on, at least in part, on signals associated with neighboring sensor elements.
• the term "local” or “localized” refers to features computed based on one or more neighboring sensor elements rather than statistical or other mathematical evaluation of the entire image.
• the sensor elements including a subject sensor element and other sensor elements relatively close to the subject sensor element may be referred to as neighboring sensor elements.
• the neighboring sensor elements may include the subject sensor element and sensor elements immediately adjacent to the subject sensor element.
• neighboring sensor elements may also include sensor elements that are relatively close to the subject sensor element and not immediately adjacent. For example, in certain instances, sensor elements within three sensor elements from the subject sensor element may still be considered neighboring sensor elements when the width or height of the number of sensors is sixty four sensor elements.
• CV features or localized CV features may refer to detecting low level computer vision markers or indicators, such as labels associated with each sensor element or pixel of the sensor.
• CV features can include outputs such as a Histogram of Signed Gradients (HSG) and/or a Local Binary Pattern (LBP).
• HSG Histogram of Signed Gradients
• LBP Local Binary Pattern
• An LBP calculation can be based on neighboring sensor elements, for example a reference or subject sensor pixel and its eight immediately-adjacent neighboring sensor pixels. The LBP calculation may score each of the reference pixel's immediately-adjacent neighboring pixels based on their respective difference in intensity. (Color would be dealt with using different LBPs for different color channels (e.g., red, blue, and green).)
• a HSG computation also employs neighboring sensor elements, for example a reference pixel and one or more
• the user 130 may have picked up the mobile device 105 while the mobile device's general -purpose microprocessor is in a sleep mode.
• the sensor system of the mobile device 105 may remain active and may be capable, for example, of recognizing the face of the user 130, a hand gesture, other objects in the scene, and/or the like.
• the sensor system can send an event to the mobile device's general-purpose microprocessor indicating that the facial features of the user 130 have been recognized and/or causing the mobile device's general-purpose microprocessor to exit the low-power mode and become fully active.
• Reference occurrences that cause the sensor system to send an event to the mobile device's general -purpose microprocessor can include any of a variety of CV- detectable occurrences, depending on desired functionality. These occurrences may include, for example, facial and/or object detection, facial and/or object recognition, gesture recognition, and/or the like. In some embodiments, one or more reference occurrences may be configurable by a user 130. Additional examples of reference occurrences are provided herein below.
• the special-purpose camera is dedicated to the sensor system, it may not be primarily intended for clicking photographs or shooting videos. Therefore, the special-purpose camera may not yield intensity -based images out. Instead, the special- purpose camera may include pixel-level computer vision feature computations like LBPs, Gradients, Edges, HSGs, and/or other operations in which readings from neighboring sensor pixels of the special-purpose camera are used to compute CV features, for a low-power hardware-based computation of the said features.
• pixel-level computer vision feature computations like LBPs, Gradients, Edges, HSGs, and/or other operations in which readings from neighboring sensor pixels of the special-purpose camera are used to compute CV features, for a low-power hardware-based computation of the said features.
• a sensor system comprising a special-purpose camera
• a sensor system can include a sensor array unit that includes sensor cells for sensing chemical, visual, aural, biological, mechanical, and/or other types of input.
• FIG. 1 and other embodiments describe a sensor system being incorporated into a mobile device, embodiments are not so limited. Power savings brought by the techniques and features described herein can have particular benefit to mobile devices—such as mobile phones, tablets, laptops, portable media players, and/or the like— but other devices, such as televisions, desktop computers, and/or other devices that may not be generally considered mobile may utilize the features and techniques described herein.
• FIG. 2 A is a block diagram that illustrates how a sensor system 210 (also referred to herein as a "smart sensor”) can be configured to enable high-level sensing operations while a main processor 220 can be operating in a low-power (e.g., "sleep" or "stand-by") mode, according to one embodiment.
• a sensor system 210 also referred to herein as a "smart sensor”
• main processor 220 can be operating in a low-power (e.g., "sleep” or "stand-by") mode, according to one embodiment.
• Components of FIG. 2A can be incorporated into a larger electronic device.
• An example of a mobile device in which a sensor system 210 may be incorporated is described below, with regard to FIG. 5.
• embodiments of a sensor system 210 may or may not include peripheral circuitry 214, a microprocessor 216, and/or memory 218. Additionally or alternatively, embodiments may combine, separate, add, omit, and/or rearrange the components of FIG. 2 A, depending on desired functionality. For example, where the sensor system 210 comprises a sensor array (e.g., a pixel array or camera), some optics may be utilized to manipulate the input (e.g., light) before it reaches the sensor array.
• a sensor array e.g., a pixel array or camera
• FIG. 2B illustrates a sensor system 210 with a sensor array unit 212, microprocessor 216, and example peripheral circuitry 214, according to one embodiment.
• a sensor system 210 receiving an input can comprise a sensor array unit 212, peripheral circuitry 214, microprocessor 216, and/or memory 218.
• the electronic sensor can be communicatively coupled through either a wired or wireless connection with a main processor 220 of an electronic device (such as an application processor of a mobile phone), which can provide queries to the sensor system 210 and receive events and/or other triggers from the sensor system 210.
• the "main processor" 220 may simply correspond to a larger, for example greater in processing power and/or greater in electric power use, processing unit than the microprocessor 216.
• microprocessor 216 can correspond to a dedicated microprocessor or a first processing unit and can be configured to consume less power than the main processor 220, which can correspond to a second processing unit.
• the type of sensor array unit 212 utilized can vary, depending on the desired functionality of the electronic sensor.
• an sensor array unit 212 can include an array (e.g., a one- or two-dimensional array) of sensor cells for sensing chemical, visual, aural, biological, mechanical, and/or other types of input.
• the sensor array unit 212 can comprise a camera sensor or other vision and/or sensor array where the plurality of sensor cells forms a grid of pixels.
• the sensor array unit 212 may include a "smart" array, that includes some additional memory and/or logic circuitry with which operations on one or more outputs of the sensor cells may be performed.
• each sensor pixel in the sensor array may be coupled with the memory and/or logic circuitry, which may or may not be part of the peripheral circuitry 214 (discussed in more detail below).
• the output of the sensor array unit 212 and/or peripheral circuitry may include outputs in addition or as an alternative to the raw sensor readings of the sensor cells.
• the sensor array unit 212 and/or peripheral circuitry can include dedicated CV computation hardware configured to receive image data from a sensor array of the sensor array unit 212 comprising more than one sensor pixel.
• CV features can then be computed or extracted by the dedicated CV computation hardware using readings from neighboring sensor pixels of the sensor array, providing outputs such as a computed HSG and/or an LBP feature, label, or descriptor.
• no image signal processing circuitry may be disposed between the sensor array unit 212 and the dedicated CV computation hardware.
• dedicated CV computation hardware may receive raw sensor data from the sensor array unit 212 before any image signal processing is performed on the raw sensor data.
• Other CV computations are also possible based on other CV computation algorithms including edge detection, corner detection, scale-invariant feature transform (or SIFT), speeded up robust features (SURF), histogram of oriented gradients (HOG), local ternary patterns (LTP), etc., as well as extensions of any of the above.
• the synchronicity (or asynchronicity) of the sensor array unit 212 may also depend on desired functionality.
• the sensor array unit 212 may comprise a traditional (i.e., "frame-based") camera with readout circuitry timed to provide periodic sampling of each pixel based on certain timing requirements.
• the sensor array unit 212 may comprise an event-driven array by which sensor output may be determined by when a sensor reading or other output reaches a certain threshold and/or changes by a certain threshold, rather than (or in addition to) adhering to a particular sampling rate.
• a smart sensor array can comprise a dynamic vision sensor (DVS) in which, for each pixel in the smart sensor array, a pixel value is asynchronously output when the value changes from a previous value by a threshold amount.
• the sensor array unit 212 can be a hybrid frame-event-driven array that reads values out at a given frame rate, but saves power by only reading out values for elements in the array that have changed since the previous read-out.
• the peripheral circuitry 214 can also vary, depending on the desired functionality of the electronic sensor.
• the peripheral circuitry 214 can be configured to receive information from the sensor array unit 212.
• the peripheral circuitry 214 may receive information from some or all pixels within the sensor array unit 212, some or all of the in-pixel circuitry of the sensor array unit 212 (in implementations with significant in-pixel circuitry), or both.
• peripheral circuitry can provide timing and/or control operations on the sensor array unit output (e.g., execute frame-based and/or similar timing).
• peripheral circuitry 214 can include an event-queuing and/or processing operation, analog processing, analog-to-digital conversion, an integration operation (e.g. a one- or two-dimensional integration of pixel values), CV feature computation, object classification (for example, cascade-classifier-based classification or histogram-based classification), or histogram operation, memory buffering, or any combination thereof, "pixel block value summation," "neighboring pixel value comparison and
• Means for performing such functionality can include, for example, peripheral circuitry 214, in various implementations.
• the peripheral circuitry 214 is coupled to the sensor cell outputs of the sensor array unit 212 and does not include a microprocessor or other processing unit. Some examples of peripheral circuitry 214 are included herein below, with regard to FIG. 2B.
• some embodiments can further include a microprocessor 216 coupled to the output of the peripheral circuitry 214.
• the microprocessor 216 generally can comprise a processing unit that operates on relatively low-power, relative to the main processor 220.
• the microprocessor 216 can further execute computer vision and/or machine-learning algorithms (which can be frame- and/or event-based) using its own program (for example, software-based) and data memory.
• the microprocessor 216 is able to perform computer vision and/or machine learning functions based on input received by the sensor array unit 212 while the main processor 220 operates in a low-power mode.
• the microprocessor 216 determines that an event requiring output to the main processor 220 has taken place, the microprocessor 216 can communicate an event to the main processor 220, which can bring the main processor 220 out of its low-power mode and into a normal operating mode.
• the output of the microprocessor 216 may further be provided to memory 218 before being relayed to the main processor 220.
• the memory 218 may include working memory and/or data structures maintained by the microprocessor 216 on the basis of which events or triggers are sent to the main processor 220. Memory may be utilized, for example, in storing images, tracking detected objects, and/or performing other operations as discussed in more detail below with regard to FIG. 2B. Additionally or alternatively, memory 218 can include information that the main processor 220 may query from the sensor system 210.
• the main processor 220 can execute application software, algorithms, etc. 222, some of which may further utilize information received from the sensor system 210.
• the ability of the sensor system 210 to perform certain functions, such as image processing and/or computer vision functions, independent of the main processor 220 can provide for vast power, speed, and memory savings in an electronic device that would otherwise have to utilize the main processor 220 to perform some or all of the functions of the sensor system 210.
• the combination, of the sensor array unit 212, peripheral circuitry 214, and microprocessor 216 allow scene understanding that is capable of detecting, in a dynamically changing scene captured by the image array, an occurrence.
• a mobile phone having the configuration shown in FIG. 2A can use facial detection to exit out of a standby mode.
• the mobile phone enters into a standby mode in which a display of the mobile phone is powered down, and the main processor 220 operates on a low-power, sleep mode.
• the sensor system 210 with an image array as the sensor array unit 212 continues to operate, processing data from the sensor array unit 212 as objects enter and exit the image array's field of view.
• a face enters the field of view of the image array (such as in FIG.
• the microprocessor 216 can send an a facial-detection event to the main processor 220, indicating that a face detection has occurred.
• the main processor 220 and the display of the mobile phone can then switch back to normal operating mode.
• an event can be an indication that one or more reference occurrences have occurred.
• events can include data related to a reference occurrence.
• the data included in an event can be indicative of a detected reference object, location information related to the reference object, number of reference objects, movement associated with detected reference object, and the like. This data may be conveyed in any of a variety of ways. For example, in the case of object detection, an event can be a simply binary output where "0" means the reference object has not been detected, and " 1" means the reference object has been detected.
• An event may include information other than an indication that a reference occurrence has occurred.
• an event may also include some data associated with the reference occurrence.
• an event may include an n- bit/byte message, or multi-field message, where each bit or field is mapped to a specific piece of data.
• an event may include an output where the first bit/field indicates whether an object has been detected, the second bit/field indicates whether the object is moving or stationary, the third bit/field relates the location of the object (or location-related information, such as four corners of a minimal box bounding the object, or location of a corner of the object, etc.), the fourth bit/field relates how many objects are detected, etc.
• the event could include any data, including the hardware- computed CV features, or the image, in any way associated with the reference occurrence, including measurements or computations related to the reference occurrence, above the mere reference occurrence.
• the reference occurrence may include any of a variety of triggers, such as a face or other object detection event, gesture event, face and/or reference object detection and/or recognition, eye or iris detection, and the like.
• Specific facial features may also be detected, such an eye, nose, or ear.
• Face detection or facial feature detection may be used to infer location of other features, for example, detection of a nose may infer location of eye(s), or vice versa.
• Face detection which can be implemented using any of a variety of face-detection algorithms, can include the coming into view of a human face or a non-human animal face (e.g., dog, cat, or other pet), or the coming into view of a human body or non-human animal body.
• Such "coming into view” of an object can be a result of movement of the object and/or movement of the camera.
• a reference occurrence may go beyond facial detection to determine an emotion or other expression of a human face from an analysis of various facial features and/or position of those features indicative of the expression.
• a reference occurrence may include detection and/or recognition of additional objects and/or object movements, such as a coming into view of a human hand, a hand gesture, a coming into view of a reference object (such as a certain object, a logo, or other reference object), and the like.
• a sensor system 210 may be preconfigured to detect certain reference objects.
• an object for detection and/or recognition by the sensor system 210 may be selectable by a user and/or application executed by the main processor 220.
• a reference occurrence may include detected environmental changes, such as a change from an indoor environment to an outdoor environment, a reference movement, rapid movement in a scene (e.g., indicating a fall), motion toward an object (e.g., indicating a risk of collision), movement or objects in a scene indicating danger (e.g., a fire for fire detection), or any combination thereof.
• a reference occurrence may be related to, or based on, the detection of a reference object, as described in further detail below in FIG. 2B and elsewhere herein.
• the detection of a reference object as described in further detail below in FIG. 2B and elsewhere herein.
• microprocessor 216 can check to see if the same object is subsequently detected in a subsequent image frame.
• the microprocessor 216 can use location information and other data associated with the detected object received from the peripheral circuitry 214, or generated by the microprocessor 216 itself, to determine the occurrence of the reference occurrence, which can be based on the detection of the reference object.
• facial detection may take place if the detection of a face (reference object) remains in the field of view of the image array for a threshold period of time, resulting in a corresponding facial-detection event being sent to the main processor 220.
• FIG. 2B illustrates an example implementation sensor system, such as the sensor system 210 of FIG. 2 A, including a sensor array unit, CV computation hardware, and microprocessor that includes an interface for communication with a second microprocessor.
• the sensor array unit 212 may include a correlated double sampling circuit.
• the sensor array unit 212 may also include circuitry to combine, sum or average sensor element or pixel signals or values before outputting the signals to line buffer(s) 230, for example in implementations where CV computation is improved using combined pixel values or a lower resolution.
• Line buffer(s) 230 may include one or more line buffers to transfer signals representing the image or portions of the image out of the sensor array unit 212 to other portions of the vision sensor.
• the senor element array 212 may not include circuitry for image signal processing (ISP), and hence, FIG. 2B illustrates an implementation where the sensor array unit 212 and CV computation hardware 242 are connected without intervening ISP circuitry, hence, in some implementations, no ISP circuitry is disposed between the sensor array unit 212 and the hardware scanning window array 238 or dedicated CV computation hardware 242.
• ISP image signal processing
• the signals received by the CV computation hardware 242 from the sensor array unit 212 have not undergone ISP, for example, the signals have not undergone one or more of defect correction, white balancing, color balancing, auto focus, lens roll off, demosaicing, debayering, or image sharpening, or any combination thereof.
• some processing may occur, such as focusing or auto-exposure correction.
• Such signals that have not undergone ISP may be referred to as raw signals or raw sensor readings or raw sensor data.
• Raw signals, raw sensor readings, or raw sensor data can be converted to digital, integrated to form an integral image, stored in a scanning window and dedicated CV computation hardware can be configured to receive the raw signals, raw sensor readings, or raw sensor data, even though it is understood that the raw signals, raw sensor readings, or raw sensor data has undergone some data manipulation (including summation or integration), but have not undergone ISP.
• the sensor array unit 212 is a Quarter Video Graphics Array (QVGA) camera sensor without ISP circuitry with the array comprising 216 by 240 sensor elements.
• QVGA Quarter Video Graphics Array
• the CV computation hardware 242 can perform CV computations in either the digital or analog domain. Therefore, optionally, in digital implementations, an analog-to-digital converter (ADC) 234 may be disposed between the line buffer(s) 230 and the CV computation hardware 242. In some implementations, the CV computation hardware 242 is dedicated CV computation hardware in the sense that it is hardware designed to have little or no functionality other than to compute CV features, labels, or descriptors.
• ADC analog-to-digital converter
• the CV computation hardware 242 may use combinations, sums, or averages of signals associated with blocks of sensor elements or pixels.
• an integral image can be useful in computing such combinations, sums, or averages prior to input into the CV computation hardware 242. For example, for summing more than four pixels (e.g., for blocks greater than 2x2, such as 3x3 or 1 lxl 1), summation can be much faster using an integral image since only four values need to be added or subtracted to determine the sum of pixel values in an integral image, rather than sum 9 or 121 values for respective 3x3 or 1 lxl 1 image blocks.
• the vision sensor may also include two dimensional integration hardware 236 for computing an integral image of at least a part of the image based on at least a subset of the signals representative of the image sampled by at least a subset of sensor elements (e.g., pixels) in the sensor array unit.
• the two dimensional integration computation hardware 236 can be in communication with the dedicated CV computation hardware 242.
• integral image representative of the image sampled by the sensor array unit and/or the integral image of a portion of the image sampled by the sensor array unit can be used to more quickly combine, sum, or average signal values for blocks of sensor elements compared to adding the signal values directly.
• Two dimensional integration hardware 236 can include circuitry capable of generating signals representative of the integral image of all or a portion of the image sampled by sensor array unit in either the digital or analog domains based on raw signals from the sensor array unit 212.
• the integral image (which may be an integral image of only a portion or sample window of the image sampled by the sensor array unit) generated by the two dimensional integration hardware 236 can be stored in a hardware scanning window array 238, as illustrated in FIG. 2B.
• the hardware scanning window array may include a random-access memory (RAM) array or other form of analog or digital memory for storing the integral image.
• the two dimensional integration hardware 236 may not be included, and hence a sample window including analog raw signals from the sensor array unit 230 or converted-to-digital raw signals from the ADC 234 may be stored directly in the hardware scanning window array 238.
• two dimensional integration hardware 236 may also or instead perform one dimensional integration.
• the hardware scanning window array 238 may store a one dimensional integral image corresponding to a sample window of the image captured by the sensor array 230.
• a frame buffer (not illustrated) may be used before or after the two dimensional integration hardware 236.
• the entire frame or image can be transferred from the sensor array unit 212 into the frame buffer.
• the two dimensional integration hardware 236 can then generate integral images of portions or windows of the image stored in the frame buffer and store such windows in the hardware scanning window array 238.
• the two dimensional integration hardware 236 can integrate the entire image and store the entire integral image in a frame buffer disposed between the two dimensional integration hardware 236 and the hardware scanning window array 238, in which case windows of the integral image stored in the frame buffer can be stored in the scanning window array 238. It is understood, however, that the frame buffer is optional and two dimensional integration hardware 236 can receive data corresponding to windows or portions of the image from the sensor array unit 212 and integrate the windows or portions one the fly and store such integral image windows in the hardware scanning window array 238.
• the vision sensor may also include CV computation hardware 242.
• the CV computation hardware can compute a localized CV feature for a block of one or more subject sensor elements based on, at least in part, signals associated with a plurality of neighboring sensor elements in proximity to the block of sensor elements.
• CV computation hardware can include hardware that receives signal values corresponding to raw image signals— or combinations, sums, or averages of raw image signals (generated, for example, using an integral image)— and generates a digital LBP label or vector based on the raw image signals.
• the block of one or more subject sensor elements can include a block of m by n sensor elements, for example, 11 by 11 sensor elements. It is also understood that a pixel-level LBP computation may also be made where the block of one or more subject sensor elements for which the localized CV feature is computed is a single subject sensor element.
• CV computation hardware 312 as separate from the dedicated microprocessor 320, it is understood that in some implementations, dedicated CV computation hardware 312 may be implemented in hardware within the dedicated microprocessor 320.
• Generating the CV features, such as the LBP labels discussed above, in dedicated hardware can reduce the power of the vision sensor compared to computing the CV features in a processor, for example a general purpose processor such as an application processor or even microprocessor 216.
• the vision sensor may still include a microprocessor 216 coupled to the CV computation hardware 242 to perform functions other than CV feature computation, such as CV-related operations or computations other than CV feature computation, or to perform additional CV feature computation relative to computations performed using CV feature computation hardware 242.
• the microprocessor 216 receives the hardware-computed CV features from the CV computation hardware 238 and can perform higher-level computer vision operations such as object-class detection (of which face detection can be regarded as a specific case, with other examples including upper torsos, pedestrians, and cars), in which the task is to find the locations and sizes of all objects in an image that belong to a given class, among other computer vision operations. Furthermore, the object-class detection (of which face detection can be regarded as a specific case, with other examples including upper torsos, pedestrians, and cars), in which the task is to find the locations and sizes of all objects in an image that belong to a given class, among other computer vision operations. Furthermore, the object-class detection (of which face detection can be regarded as a specific case, with other examples including upper torsos, pedestrians, and cars), in which the task is to find the locations and sizes of all objects in an image that belong to a given class, among other computer vision operations. Furthermore, the object-class detection (of which face detection can be regarded
• microprocessor 216 can provide control signals to the line buffer(s) 230, ADC 234, two dimensional integration hardware 236, hardware scanning window array 238, and CV computation hardware 242.
• the microprocessor 216 may use a cascade classifier algorithm to perform object-class detection, for example face detection.
• further power savings are possible by implementing the cascade classifier in hardware, to further reduce the computational burden on the microprocessor 216.
• the optional cascade classifier hardware 244 includes a hardware
• the cascade classifier is trained using machine learning techniques on a data set of images including examples of the reference object the cascade classifier will be trained to detect or classify and examples of non-objects, for example images of faces and non -faces, or images of cars and non-cars, or images of upper torsos and non-upper torsos, etc.
• the cascade classifier hardware may request the CV computation hardware 242 to compute LBP features for a certain number, /, of subject sensor elements stored in, for example, the hardware scanning window array 238.
• the location of the subject sensor elements ⁇ (xii, yn), ...
• each LBP feature (LBPn, ... , LBPi ) will be multiplied by a given weight, (wn, ... , wi/), each of which can be different.
• the first weighted scalar sum value is then compared to a first threshold.
• the cascade classifier hardware 244 sends a signal to the hardware scanning window array 238, and optionally to other components of the vision sensor, such as the line buffer(s) 230 and the sensor array unit 212, to indicate that the hardware scanning window array 238 should continue scanning and add one or more new columns and/or rows and remove one or more old columns and/or rows.
• the process can begin anew.
• the subsequent window of the image may overlap in large part with the previous window of the image.
• the image is scanned from left to right, and once the end of the sensor array unit 212 is reached, the image may be scanned again from left to right after moving down one or more rows. In another implementation, the image may be scanned from right to left after shifting down by one or more rows which may allow for an increased overlap with the prior image.
• the cascade classifier hardware 244 moves to the next stage.
• the cascade classifier hardware again requests the CV computation hardware 242 to provide LBP features for m subject sensor elements at locations ⁇ (x2i, y 21 ), ... (x2m, yim) ⁇ stored in the hardware scanning window array 238.
• the cascade classifier hardware 244 performs another summation of a dot product of each of the LBP features with one or more weights, (w2i, ...
• the second weighted scalar sum value is then compared to a second threshold. If the scalar sum is less than the second threshold, there is a low likelihood of a reference object being present in the portion of the image represented by the signals stored in the hardware scanning window array 238, and the cascade classifier sends a signal to the other components in the vision sensor array to continue scanning and move to a next portion of the image. If the second weighted scalar sum value is greater than the second threshold, the process continues to a third stage as described above.
• a reference object is detected in the portion of the image stored in the hardware scanning window array 238.
• the cascade classifier hardware 244 can then indicate to the microprocessor 216 that the reference object has been detected, and may further optionally indicate the location of the portion of the image in which the reference object, or portion of reference object, was detected.
• the cascade classifier hardware 244 can be configured to send an indication to the microprocessor 216 that the reference object was detected along with data associated with the reference object, such as the all or some of the CV features computed in the process of detecting the reference object, the location within the image of those CV features, or any other data associated with the computations or operations performed by the CV computation hardware 242 and/or the cascade classifier hardware 244.
• a cascade classifier can include between 1 and 31 stages, for example, 16 stages. In some implementations, a cascade classifier can include between 1 and 31 stages, for example, 16 stages.
• Cascade classifier hardware 244 can, in some implementations, be considered dedicated cascade classifier hardware in the sense that it is hardware designed to perform the cascade classifier function and little to no other significant functions. While the implementation described above relates to a cascade classifier based on programmed weights and thresholds based on previous, in the laboratory, training and machine learning to generate a model, it is understood that cascade classifier hardware 244, or other hardware in peripheral circuitry designed to perform CV operations based on hardware- computed CV features received from CV computation hardware 242, can be designed to perform machine learning in the field.
• the microprocessor 216 can then determine what to do with the, for example, reference object detected event. For example, it may send an event to a second microprocessor.
• the microprocessor 216 and the second microprocessor may correspond to microprocessor 216 and the main processor 220 of FIG. 2A.
• the microprocessor 216 includes an interface 246 for communications with the second microprocessor.
• the microprocessor 216 might track a position of the detected reference object over time (e.g., over multiple images) to determine movement for gesture recognition, risk of collision, danger, and/or other events, for example.
• some embodiments can enable a wide range of functionality by first detecting an object then determining other features.
• object detection may be made via peripheral circuitry (e.g., cascade classifier hardware 244 and/or other dedicated hardware), and additional operations may be performed by a microprocessor 216.
• a coming into view of an object may be determined first by detection of the object, then (e.g., using a microprocessor) a determination that the object has been in the camera's field of view for a threshold period of time.
• Gesture detection as noted above, may be made by detecting a gesture-control object (e.g., a hand), then determining the movement of the hand.
• a gesture-control object e.g., a hand
• Risk of collision may be made by detecting an object and determining movement indicative of risk of collision with the object (e.g., by the camera, by a second object within the camera's field of view, etc.).
• determining movement indicative of risk of collision with the object e.g., by the camera, by a second object within the camera's field of view, etc.
• embodiments may include any combination of the features above, and/or variations on these features.
• cascade classifier hardware 244 may be implemented in hardware within the microprocessor 216. Also, cascade classifier hardware 244 can, in some implementations
• control CV computation hardware 242 and hardware scanning window array 238 can be given some controlling functionality to allow it to, as illustrated, control CV computation hardware 242 and hardware scanning window array 238.
• the cascade classifier hardware 242 can detect features autonomously from microprocessor 216, and hence microprocessor 216 can be in a low-power state while cascade classifier hardware 244 performs its functions.
• the smart sensor can perform lower-power operations based on the one or more computed CV features, and when an object, for example, is detected, cascade classifier hardware 242 can provide an event, including data such as a sensor reading to the microprocessor 216, to awaken the microprocessor 216.
• Microprocessor 216 can then determine the next course of action, for example sending an event to a second microprocessor through interface 246.
• microprocessor 216 can, in some implementations, still provide control signals to sensor array unit 212, line buffer(s) 230, etc., or, alternatively or additionally, such control signals may be provided by lower power control logic.
• a cascade classifier may be run as a software algorithm on the microprocessor 216.
• other software algorithms may be run on the microprocessor in the place of the cascade classifier. For example, reference object detection may be performed using histograms, as described in FIG. 11C.
• a histogram of all LBP labels computed for a sample window of the image stored in the scanning window array 238 can be compared to a reference histogram to detect the presence of a face in the sample window stored in the scanning window array 238.
• dedicated hardware may be implemented to detect, for example, a face using histograms. Such an implementation may include such dedicated hardware in the place of, or in addition to, cascade classifier hardware 244.
• one or more of the line buffer(s) 230, the ADC 234, the two dimensional integration hardware 236, the hardware scanning window array 238, the CV computation hardware 242, the cascade classifier hardware 244, or any combination thereof may be considered peripheral circuitry, that is circuitry that is peripheral to the sensor array unit 212 and may correspond to peripheral circuitry 214 of FIG. 2A. It is also understood that the various components just listed, or any combination thereof, may be implemented instead as in-pixel circuitry within the sensor array unit 212.
• FIGS. 3A-3C are block diagrams illustrating how components of a sensor system 210 can be utilized to provide low-power sensor processing. Here, only certain components are illustrated. It will be understood that the sensor system may have additional components, as shown in FIGS. 2 A and 2B.
• peripheral circuitry 214 is coupled with a plurality of sensor cell outputs of a sensor array unit 212.
• the sensor array unit 212 and/or peripheral circuitry 214 include dedicated CV computation hardware to perform a feature detection computation using at least a subset of the plurality of sensor cell outputs, where the subset of the plurality of sensor cell outputs correspond to a region of the sensor array unit 212 (e.g., an image array) comprising neighboring sensor cells or pixels.
• the output of the peripheral circuitry 214 is based (at least partially) on the feature detection computation.
• Such feature detection computation can include any of a variety of computations using neighboring sensor cells or pixels of the sensor array unit 212 that can provide for feature detection (e.g., edge detection, line detection, etc.).
• feature detection computations include, for example, LBP, HSG, and the like.
• the dedicated CV computation hardware may comprise an integrated circuit.
• a first processing unit 217 is communicatively coupled with one or more outputs of a smart image array 213, in which multiple sensor pixels are coupled with memory and/or logic circuitry.
• the first processing unit 217 may correspond to the microprocessor 216 of FIGs. 2 A and 2B
• the smart image array 213 may correspond to the sensor array unit 212 of FIGs. 2 A and 2B.
• the smart image array 213 may include dedicated CV computation hardware for computing CV features computed using readings from neighboring sensor pixels, as described above in regard to FIG. 3 A and/or FIG. 2B. As shown in FIGs. 2A and 2B, these two components may not be directly coupled to each other, but may have intervening circuitry.
• the first processing unit 217 processes signals received from the one or more outputs of the smart image array to detect a reference occurrence.
• the first processing unit 217 then generates an event, indicating the reference occurrence, to be received by a second processing unit (e.g., the main processor 220 of FIG. 2A).
• a second processing unit e.g., the main processor 220 of FIG. 2A.
• the event can be generated based on processing signals resulting from operations that are based on one or more computed CV features.
• Such operations can include, in some implementations, operations or computations performed by the cascade classifier (e.g., cascade classifier hardware 244 of FIG. 2B) to detect a face.
• the event being generated based on processing signals resulting from those operations may therefore include the microprocessor processing a signal, such as an indication from the cascade classifier, that a reference object was detected.
• the indication may include data associated with the detected object, such as the location, associated LBP features and their locations, and/or the image data itself. This enables the microprocessor to conserve energy by not analyzing image data when no reference object is detected.
• a first processing unit 217 is communicatively coupled with one or more outputs of an image array 216.
• the first processing unit 217 may correspond with the microprocessor 216 of FIG. 2 A and/or 2B, and the image array 216 may similarly correspond with the sensor array unit 212 of FIG. 2A and/or 2B.
• the first processing unit 217 determines that a face has been detected and generates the face-detection event for a second processing unit.
• the first processing unit 217 may be operable to detect a face using the one or more signals received from the one or more outputs of the image array 216. While the implementations illustrated in FIGS.
• the dedicated microprocessor (such as microprocessor 216 with reference to FIGS. 2 A and 2B and first processing unit 217 with reference to FIGS. 3B and 3C) may interface with circuitry that would not traditionally be considered a processor, such as an I/O device controller. Such implementations may be referred to as single-processor implementations. As described further below, in alternative embodiments, the I/O device controller may also be implemented within the dedicated microprocessor.
• FIG. 4 is a flow diagram illustrating a method 400 of sensing dynamic scene- based occurrences, according to an embodiment.
• FIG. 4 is provided as a non-limiting example.
• Alternative embodiments may include additional functionality to that shown in the figure, and/or the functionality shown in one or more of the blocks in the figure may be omitted, combined, separated, and/or performed simultaneously.
• Means for performing the functionality of the blocks may include one or more hardware and/or software components of an electronic device, such as one or more components of the mobile device illustrated in FIG. 5 and described below.
• a person of ordinary skill in the art will recognize many variations.
• the method 400 can begin at block 410, where dedicated CV computation hardware receives image data from a sensor array.
• the image data can include sensor readings from a plurality of image pixels of the sensor array.
• the dedicated CV computation hardware may be implemented in and/or incorporated into the sensor array unit 212 and/or peripheral circuitry 214 of FIG. 2A. (The sensor array can be included in the sensor array unit 212.)
• CV features is computed by the dedicated CV computation hardware using readings from neighboring sensor pixels of the sensor array.
• CV features can include edges, lines, and the like, which may be computed using, for example, LBP, HSG, and/or other computations.
• the usage of the dedicated CV computation hardware can enable quick and efficient computations without the need to use comparatively higher amounts of energy and/or processing power.
• one or more CV operations are performed based on the one or more CV features.
• such operations can occur in peripheral circuitry.
• a cascade classifier may perform operations to detect a face or other object, and provide a signal indicative of the detection of the face or other object to a microprocessor.
• performing CV operations based on one or more CV features can be performed by either or both peripheral circuitry (e.g., dedicated hardware) and/or a microprocessor.
• the hardware and/or software components performing the CV operations can produce output signals (e.g., an output of a cascade classifier, signals indicating the LBP computations received directly from the CV computation HW, signals internally generated within the microprocessor, etc.).
• the microprocessor may use one or more of these signals to determine a reference occurrence (e.g., face detection) has happened.
• a reference occurrence can include one or more of a variety of events. These can include, for example, a coming into view of a human face, an emotion expressed on a human face, coming into view of an non-human animal face, coming into view of a human hand, a hand gesture, a coming into view of a reference object, a change from an indoor environment to an outdoor environment, a reference movement, rapid movement in a scene indicating a fall, motion toward an object indicating a risk of collision, movement or objects in a scene indicating danger, or any combination thereof. In some embodiments, these reference occurrences may be predefined and/or user configurable.
• an event for a second processing unit is generated, where the event is indicative of the reference occurrence.
• the term "event” describes information provided to a processing unit, indicative of a reference occurrence.
• the event is provided to a second processing unit.
• the event may simply include an indication that a reference occurrence has happened.
• the event may further include an indication of the type of reference occurrence that was detected.
• the event may be generated by the first processing unit and sent to the second processing unit. In some embodiments, there may be intervening circuitry between the first and second processing units.
• the functionality performed by the various blocks illustrated in FIG. 4 can be performed by various components of a sensor system (e.g., sensor system 210 of FIGS. 2A and 2B), depending on desired functionality.
• the functionality of block 410 and 420 may be performed by in-pixel or peripheral circuitry (e.g., CV computation hardware).
• the functionality of block 425 may be performed by a microprocessor or dedicated hardware (e.g., a cascade classifier or other dedicated hardware).
• the functionality of blocks 425, 430, and 440 may all be performed by a microprocessor.
• some embodiments may perform the functionality of block 425 with peripheral circuitry, and the functionality of blocks 430 and 440 with a microprocessor.
• a person of ordinary skill in the art will recognize several variations.
• embodiments of the sensor system 210 described herein can further perform different types of functions, such as lower-power operations and higher-power operations, which relate to power or energy consumption used in respective lower-power and higher-power modes.
• the sensor system may provide image processing capabilities within the sensor system 210 itself by utilizing dedicated CV computation hardware as described herein. It is understood that the use of "lower-power" and “higher-power” herein is intended to be relative. In other words, even in the higher-power mode, the sensor system described may still be capable of performing powerful CV-based computations based on hardware-computed CV features using less power than performing those same CV- based computations with a microprocessor running CV algorithms in software.
• dedicated CV computation hardware can include in-pixel circuitry integrated into the sensor array unit 212, which may include circuits for some or all pixels, capable of performing processing on each respective pixel, such as detecting a sensed light intensity relative to one or more neighboring pixels, detecting edges of objects based on differences in colors or intensities of sensed light with respect to neighboring pixels, and/or making LBP, HSG, and/or other CV computations.
• Dedicated CV computation hardware can further include peripheral circuitry 214, which can be used in addition or alternatively to in-pixel circuitry to perform some or all of these computations. Embodiments may disable, or otherwise operate in a low-power mode, some or all of this dedicated CV computation hardware of the sensor system 210 when higher-power operations are not needed, which can save power. Thus, as described herein, higher-power operations involve dedicated CV computation hardware (e.g., in-pixel circuitry in the sensor array unit 212 and/or peripheral circuitry 214), whereas lower-power operations are performed when some or all of the dedicated CV computation hardware is disabled or in a reduced-power state.
• peripheral circuitry 214 can be used in addition or alternatively to in-pixel circuitry to perform some or all of these computations. Embodiments may disable, or otherwise operate in a low-power mode, some or all of this dedicated CV computation hardware of the sensor system 210 when higher-power operations are not needed, which can save power.
• higher-power operations involve dedicated CV computation hardware (e.g., in
• the sensor system 210 can configure the sensor array unit 212 to operate as a single pixel. In such a case, the sensor system 210 can disable all in- pixel circuits and/or and peripheral circuitry 214. In such a configuration, each of the individual pixels of the array contributes to a single sensed value for the entire sensor array.
• FIG. 5 shows a simplified illustration of the sensor array unit 212 of FIG. 2 A.
• pixels 510 are arranged in rows and columns and placed in the focal plane of a receiving optics to provide image capture. (For clarity, only a few pixels 510 in FIG. 5 have numerical labels.) It will be understood that features of the sensor array unit such as pixel size, aspect ratio, resolution, and the like can vary depending on desired functionality. For instance, the simplified illustration of FIG. 5 shows a 10x10 pixel array, but embodiments may have hundreds, thousands, or millions of pixels (or more).
• each pixel 510 may include a sensor as well as in- pixel circuitry to perform CV calculations for the pixel 510. Additionally or alternatively, peripheral circuitry may be included to perform CV calculations for the pixel, as indicated elsewhere herein.
• one or more components in in-pixel circuitry of the sensor array unit 212 and or peripheral circuitry may be disabled to enable the sensor array unit 212 to perform lower-power operations in a power efficient manner to, for example, turn of all but one pixel, or read and combine sensed values from all pixels to effectively operate as only a single pixel, referred to as a "single-pixel mode.”
• the sensor system 210 is configured to perform one or more lower-power operations, such as ambient light sensing (ALS), proximity detection (PD), proximity to a reference object detection, or motion detection.
• ALS ambient light sensing
• PD proximity detection
• proximity to a reference object detection or motion detection.
• each of these functions may be adequately performed using a sensor array having only a single pixel.
• the sensor array unit 212 may enable in a lower- resolution configuration in which, rather than effectively operating as only a single pixel, the sensor array unit 212 may operate as a plurality of pixels. As shown in FIG. 6, subgroups 610 of pixels 510 of the sensor array unit 212 can each operate in a manner similar to the single-pixel mode described above, thereby effectively operating as a sensor with multiple pixels (in the configuration of FIG. 6, the four subgroups 610 effectively form a 2x2 pixel array). Again, for example, some or all of the dedicated CV computation hardware of the sensor system 210 (e.g., peripheral circuitry 214 and/or in-pixel circuitry of the sensor array unit 212) can be disabled during this mode.
• the dedicated CV computation hardware of the sensor system 210 e.g., peripheral circuitry 214 and/or in-pixel circuitry of the sensor array unit 212
• the sensor system 210 may perform one or more lower-power operations, such as ALS, PD, change detection (CD), or motion detection (MD).
• lower-power operations such as ALS, PD, change detection (CD), or motion detection (MD).
• FIG. 6 employs an apparent resolution of 2x2 pixels
• other reduced resolutions may be configured. Again, such reduced resolutions may include aggregating multiple individual pixels 510 to operate collectively as a fewer number of pixels, or may include disabling one or more of the pixels 510 in the sensor array unit 212 such that the pixel does not sense light or does not provide an output while it is disabled.
• the sensor system 210 may be configured to detect one or reference occurrences and generate one or more corresponding events while it is performing in a lower-power operation.
• the sensor system 210 may be incorporated into a mobile phone and configured to detect a reference occurrence when a sensed value for the single pixel 310 indicates a significant increase in an amount of light detected by the sensor system 210. Such a change in the amount of detected light may indicate that the mobile phone has been retrieved from a user's pocket or has been picked up from a table or nightstand.
• the sensor system 210 can determine, while in lower-power operation, that this reference occurrence happened and generate an event indicative of the reference occurrence for the main processor 220. Upon detecting this event, the sensor system 210 can further activate dedicated CV computation hardware to enable higher-power operation to perform different types of CV operations, such as face detection and face recognition.
• FIG. 7 is a simplified flow diagram illustrating an example method 700 for using a sensor system as an optical sensor.
• FIG. 7 is provided as a non-limiting example. Additionally, the method 700 may apply broadly to embodiments described herein, including the method 400 of sensing dynamic scene-based occurrences shown in FIG. 4.
• Means for performing the functionality of the blocks illustrated in FIG. 7 may include one or more hardware components of the sensor system, such as the sensor system 210 of FIG. 2 A. In some embodiments, means may further include a main processor, such as the main processor 220 of FIG. 2 A.
• the method 500 is described below as being performed by the sensor system 210 of FIG. 2A, embodiments are not limited to such a sensor system.
• the method 700 can begin at block 710 when the sensor system 210 initiates a lower-power operation.
• the sensor system 210 initiates one of an ALS operation, a PD operation, CD operation, or a MD operation.
• the sensor system 210 initiates the lower-power operation by disabling dedicated CV computation hardware, and configures the sensor array unit 212 to operate at a reduced resolution.
• the reduced resolution may include a single-pixel mode.
• the sensor system 210 may initiate a plurality of lower-power operations, such as both an ALS operation and a PD operation, a CD operation and MD operation, or all four of an ALS operation, a PD operation, CD operation, and a MD operation. After initiating the lower-power operation, the method 700 proceeds to block 720.
• a plurality of lower-power operations such as both an ALS operation and a PD operation, a CD operation and MD operation, or all four of an ALS operation, a PD operation, CD operation, and a MD operation.
• the sensor system 210 while performing the lower-power operation, the sensor system 210 detects a reference occurrence.
• the sensor system 210 In one example in which the sensor system 210 is configured to perform an ALS function, the sensor system 210 generates at least one lower-power optical sensor reading, which may be used to detect the reference occurrence.
• a lower-power optical sensor reading may indicate a change in an amount of ambient light, and the sensor system 210 may detect a reference occurrence based on the lower-power optical sensor reading when a sensed level of light changes at a rate above a reference threshold, or changes color at a rate above a reference threshold.
• the sensor system 210 is configured to perform a PD function.
• the sensor system 210 further comprises a light emitter, such as a light emitting diode (LED), and the sensor array unit 212 is configured to detect an amount of reflected light.
• the sensor system 210 detects a reference occurrence.
• the sensor system 210 may detect a reference occurrence indicating an object is near the sensor system 210.
• the sensor system 210 may detect a reference occurrence.
• the sensor system 210 may detect an event that an object is no longer near the sensor system 210.
• the sensor system 210 is configured to perform a CD function.
• Change detection can detect a change in the scene that exceeds a threshold where such a scene change corresponds to a reference occurrence, for example, as described in block 720 of FIG. 7.
• hardware scanning window array 238, CV computation hardware 242, cascade classifier 244, and/or dedicated microprocessor 216, or any combination thereof may be disabled or in a low- power mode. As used here, disabled is intended to indicate that such components are in a reduced power state as their functionality is either not being utilized or their functionality is drastically reduced compared to their normal operation.
• the sensor system can operate in a lower-power mode compared to normal operation involving CV feature computation and subsequent CV operations.
• Pixel values for large blocks of pixels in the sensor array unit 212 for example as illustrated in FIG. 6 blocks corresponding to subgroups 610, can be summed to get a single value representing all pixel values in each block.
• Such a summation can be computed using an integral image provided by the two-dimensional integration hardware 236 and stored, for example, in an integral image frame buffer (not shown in FIG. 2B). The block summations can then be compared from frame to frame in time.
• a scene change reference occurrence In a given block, if the change in the summation value from a current frame compared to a previous frame is greater than a reference change threshold, then a scene change reference occurrence can be detected.
• a scene change reference occurrence will be detected only if a reference minimum number of blocks register such a change. For example, in a system with the sensor element array divided into 81 blocks (pixels are grouped into a 9 by 9 array, where each block in the 9 by 9 array includes a subarray of pixels), change in each block can be detected as described above, and a scene change reference occurrence may only be triggered if three, four, or another number of blocks register a change.
• the sensor system 210 can further activate any combination of hardware scanning window array 238, CV computation hardware 242, cascade classifier 244, and/or dedicated microprocessor 216. It is understood that CD operation described above may be implemented without the use of an integral image or two-dimensional integration hardware, but may use other hardware to determine the summed block values.
• the sensor system 210 can be configured to perform a MD function.
• the sensor system 210 configures the sensor array unit 212 to have a reduced resolution greater than a 2x2 pixel resolution, but less than a maximum resolution of pixels in the sensor array unit 212.
• the sensor system 210 is configured to detect relative changes in sensed light at different effective pixels.
• the sensor system 210 analyzes an amount of light sensed at each of the effective pixels (e.g., subgroups 610 as shown in FIG. 6), determines a first set of differences between the amount of light sensed at each effective pixel relative to at least one other effective pixel.
• the sensor system 210 then detects a second amount of sensed light at each of the effective pixels, and determines a second set of differences between the amount of light sensed at each effective pixel relative to at least one other effective pixel. The sensor system 210 then determines a change in the differences based on the first set and the second set. The sensor system 210 detects a reference occurrence if the change in the differences exceeds a reference motion threshold. In one aspect, the sensor system 210 may detect a motion event if a first effective pixel indicates a positive change in sensed light relative to a second effective pixel, and subsequently the first effective pixel indicates a negative change in sensed light relative to a second effective pixel.
• the detection of the reference occurrence at block 720 can then trigger the initiation of at least one higher-power operation.
• the sensor system 210 initiates a higher-power operation by enabling dedicated CV computation hardware.
• the sensor system 210 may initiate a face detection operation or a face recognition operation, or a gesture recognition operation.
• the sensor system 210 may initiate an object detection operation to detect the presence of a reference object in the images captured by the sensor system 210.
• the higher-power operation is based on a one-way dependence relationship between the lower-power operation and the higher-power operation.
• the one-way dependence relationship in this example relates to the higher-power operation only occurring after the lower-power operation detects a reference occurrence.
• the higher-power operation may be based on evaluating the at least one lower-power optical sensor reading.
• the sensor system 210 may perform a lower-power ALS operation and initiate a higher-power operation.
• the higher-power operation may also evaluate the sensor reading from the lower-power ALS operation.
• a higher-power operation may include a face detection or recognition function.
• the sensor system 210 may evaluate the ALS sensor reading to determine an ambient light level and adjust an exposure time or an aperture size when performing the face recognition function.
• a PD function may generate a sensor reading that a higher-power operation may evaluate to determine an estimated range to a detected object.
• the sensor system 210 may initiate other or multiple higher-power operations. In some aspects, the sensor system 210 may repeatedly execute the method 700. For example, after performing a higher-power operation, the sensor system 210 may restart the method 700 and perform the functionality at block 710 by initiating a lower-power operation. Upon detecting the scene change, for instance, the sensor system 210 can further activate any combination of additional components (e.g., hardware scanning window array 238, CV computation hardware 242, cascade classifier 244, and/or microprocessor 216) to perform one or more higher-power operations. The sensor system 210 may then revert back to a lower-power mode once the higher-power operations are performed. [0091] While the method 700 of FIG.
• the sensor system 210 may substantially simultaneously perform both lower-power and higher-power operations. For example, at block 730, after performing the higher-power operation, the sensor system 210 may initiate a lower-power operation but continue to perform higher-power operations. Thus, in some examples, at block 710, while the sensor system 210 is performing a lower-power operation, the sensor system 210 may also be performing additional functions, such as higher-power operations, and by initiating a lower-power operation, the sensor system 210 may not be exclusively performing lower-power operations. Further, when the sensor system 210 initiates a higher-power operation at block 730, the sensor system 210 in some examples may continue to perform lower- power operations.
• FIG. 8 shows an example method 800 for using a sensor system as an optical sensor. Again, the method 800 will be discussed with respect to the example sensor system 210 shown in FIG. 2A, but is not limited to such a sensor system.
• the method 800 begins at block 810, where the sensor system 210 initiates a lower-power operation as discussed above with respect to the method 700 of FIG. 7.
• the sensor system 210 detects a reference occurrence as discussed above with respect to the method 700 of FIG. 7. After detecting the reference occurrence, the method 800 proceeds to block 830.
• the sensor system 210 provides a parameter value for a higher- power operation.
• the sensor system 210 provides a level of ambient light as a configuration setting for a higher-power operation.
• the sensor system 210 may provide the parameter value as a configuration setting associated with a light intensity or auto-exposure parameter, or with an integration time for an image.
• the sensor system 210 provides an estimated distance to an object. In one such example, if the sensor system 210 performed a PD operation and detected an object, the sensor system 210 provides an estimated distance to the object or an amount of detected reflected light. In another example, the sensor system 210 provides a direction of motion to a higher-power operation.
• the sensor system 210 may be configured to perform a lower-power MD operation and/or movement of a block registering change (see discussion of CD, above) and detect a direction of motion based on changes in relative amounts of sensed light over time.
• the direction of motion may be provided to a higher-power operation, such as a gesture detection operation.
• the sensor system 210 may be configured to provide a parameter that indicates whether a scene viewed by the sensor system 210 is likely an indoor scene or an outdoor scene. For example, if a level of ambient light is above a pre-defined threshold, the sensor system 210 may provide a parameter indicating that the scene is an outdoor scene, while if the ambient light is below a second pre-defined threshold, the sensor system 210 may provide a parameter indicating that the scene is an in scene. In some examples, an indoor/outdoor determination may be made based on a peak intensity detected at one or more frequency.
• the sensor system 210 may be configured to provide a parameter indicating a region of interest in the scene.
• the sensor system 210 has configured the sensor array unit 212 to operate in a reduced resolution of 3x3 effective pixels.
• the sensor system 210 may determine an effective pixel of interest, which may be based on detected changes in ambient light, a proximity detection reference occurrence, change detection in one or more of the effective pixels, and/or a detected direction of motion.
• the sensor system 210 may be configured to provide a parameter associated with a reference occurrence frequency. In this example, the sensor system 210 detects multiple occurrences of an event and determines a frequency at which the event occurs.
• a parameter may be used to determine a higher-power operation.
• a parameter may indicate a CV feature selection operation.
• the parameter may indicate whether to use an LBP function, an HSG function, or a CV function based on intensity of light.
• the sensor system 210 initiates a higher-power operation using the parameter (provided at block 830) as discussed above.
• the sensor system 210 may substantially perform both lower-power and higher-power operations simultaneously. For example, at block 840, after performing the higher-power operation, the sensor system 210 may initiate a lower-power operation but continue to perform a higher-power operation. Thus, in some examples, at block 810, while the sensor system 210 is performing a lower-power operation, the sensor system 210 may also be performing additional functions, such as higher-power operations, and by initiating a lower-power operation, the sensor system 210 may not be exclusively performing lower-power operations.
• the sensor system 210 when the sensor system 210 initiates a higher-power operation at block 840, the sensor system 210 in some examples may continue to perform lower-power operations.
• the sensor system 210 may continue to operate with the dedicated CV computation hardware enabled.
• the lower-power operations may simply not utilize the dedicated CV computation hardware.
• FIG. 9 shows an example method for using a sensor system as an optical sensor. As with other methods described herein, the method 900 will be discussed with respect to the example sensor system shown in FIG. 2A, but is not limited to such a sensor system.
• the method 900 begins at block 910, where the sensor system 210 initiates a higher-power operation as discussed above.
• the sensor system 210 detects a reference occurrence, such as face detection or face recognition, based on the higher-power operation at block 910. After detecting the reference occurrence, the method 900 proceeds to block 930.
• the sensor system 210 provides a parameter for lower-power operation.
• a higher-power operation may detect an object near the sensor system 210, and in some example systems may also determine an estimated distance to the object.
• the sensor system 210 may provide an event comprising a parameter to the lower-power operation indicating the presence of the object, or may also (or instead) provide a parameter indicating a distance to the object.
• a parameter may be employed by the lower-power operation to assist with or enhance a PD function.
• the PD function may be able to more accurately detect an object near the sensor based on the parameter, such as by establishing or adjusting a threshold intensity level.
• the sensor system 210 can provide a parameter indicating a direction to a light source.
• a higher-power operation may detect an illuminated object or a reflective object, and a location or a direction to the object.
• the sensor system 210 may provide a parameter based on the higher-power operation indicating a direction to the light source.
• the lower-power operation may employ this parameter, for example when performing ALS.
• the higher- power operation may determine that a scene viewed by the sensor system 210 is an indoor or an outdoor scene.
• the sensor system 210 may provide a parameter to the lower-power operation.
• the parameter may assist or enhance the lower- power operation, such as by assisting with an ALS function by providing information associated with a threshold for detecting changes in ambient lighting.
• the example sensor system 210 provides a parameter indicating an indicator of occupancy of a room or of a number of people visible in a scene viewed by the sensor system 210.
• a higher-power operation may detect one or more faces, or one or more people, in a scene viewed by the sensor system 210.
• the sensor system 210 may then provide a parameter indicating a number of people or faces in a scene, or an indicator of a level of occupancy of an area.
• a lower-power operation such as a MD function, may use such information to better detect motion, or to reduce a sensitivity of the MD function to motion.
• the MD function may switch to a predetermined threshold that requires a stronger indication of motion and thus the MD function is less sensitive to motion.
• a MD function may increase its sensitivity when detecting motion events.
• a higher power operation may set the threshold and/or the minimum number of blocks for the CD operation described above.
• the sensor system 210 initiates a lower-power operation using the parameter.
• the sensor system 210 may initiate a lower-power operation as described above with respect to FIGS. 7 and 8.
• the lower- power operation after initiation, is configured to use the parameter.
• a PD function may be able to more accurately detect an object near the sensor based on the parameter, such as by establishing or adjusting a threshold intensity level.
• the parameter may assist or enhance the lower-power operation, such as by assisting with an ALS function by providing information associated with a threshold for detecting changes in ambient lighting.
• Some embodiments may repeatedly execute the method 900. For example, after performing a higher-power operation, the sensor system 210 may restart the method 900 and initiate a lower-power operation at block 910.
• the sensor system 210 may substantially perform both lower-power and higher-power operations simultaneously. For example, at block 940, after performing the lower-power operation, the sensor system 210 may initiate a higher-power operation but continue to perform lower-power operations. Thus, in some examples, at block 910, while the sensor system 210 is performing a higher-power operation, the sensor system 210 may also be performing additional operations, such as lower-power operations, and by initiating a higher-power operation, the sensor system 210 may not be exclusively performing higher-power operations. Further, when the sensor system 210 initiates a lower-power operation at block 940, the sensor system 210 in some examples may continue to perform higher-power operations.
• one or more methods may be combined.
• the methods of FIGS. 7 or 8 may be combined with the method of FIG. 9.
• the method may proceed to block 920 of the method 900 of FIG 9.
• the method may proceed to block 920 of the method 900 of FIG 9.
• Still further combinations are contemplated as well.
• FIG. 10A shows an example state diagram for computer-vision computations and lower-power optical sensor readings, which may be performed by the sensor system 210.
• FIG. 10A includes two states, a lower-power operation(s) state 1010 and a higher- power operation(s) state 1020.
• a lower-power operation(s) state 1010 the sensor system 210 is configured to perform one or more lower-power operations and may obtain one or more sensor readings.
• a higher-power operation(s) state 1020 the sensor system 210 is configured to perform one or more higher-power operations, such as computer-vision computations and operations, and may obtain one or more sensor readings.
• the sensor system 210 is configured to be in either the lower-power operation(s) state 1010 or the lower-power operation(s) state 1020, but not both simultaneously.
• the sensor system 210 is configured to transition from one state to the other based on sensor readings, which may establish a one-way dependence relationship between the states. For example, in one example, execution of a higher-power operation is dependent on a sensor reading from a lower- power operation, or execution of a lower-power operation is dependent on a sensor reading from a higher-power operation.
• the sensor system 210 may be configured to operate in both states 1010, 1020 substantially simultaneously.
• the sensor system 210 may comprise a plurality of sensor array units 212, one of which may be configured to perform lower-power operations and another of which may be configured to perform higher-power operations.
• the sensor system 210 may subdivide a sensor array unit 212 such that a portion of the sensor array unit 212 is configured to perform a lower-power (or operations), while another portion of the sensor array unit 212 is configured to perform a higher-power operation (or operations).
• a one-way dependence relationship may be established based on a sensor reading from one of the states that causes the initiating of a specific operation in the other state or causes a reconfiguring of an operation in the other state.
• an operation in one state may provide one or more parameter values usable by an operation in the other state, such as may be seen in FIG. 10B.
• FIG. 10B shows an example state diagram for computer-vision computations and lower-power optical sensor readings, which may be performed by the sensor system 210.
• FIG. 10B includes the states described above with respect to FIG. 10A, but also includes state transitions or information passing between states 1010, 1020 in response to event detections in one or both of the states 1010, 1020.
• the sensor system 210 may transition between the two states 1010, 1020 in sequence, or may operate in both states 1010, 1020 simultaneously.
• the sensor system 210 can be configured to detect events in each of the states. Examples of reference occurrences are described earlier in this disclosure.
• the sensor system 210 provides one or more parameter values based on a detected event from a function in one state to one or more functions in the other state.
• the sensor system 210 For example, if the sensor system 210 is performing a PD operation in a lower- power operation state 1010 and detects an object near the sensor system 210, the sensor system 210 provides a parameter value, such as a flag value indicating an object is detected or an estimated range to the object, to a computer-vision function in the higher- power operation state 1020, such as a face detection function. In some situations, the sensor system 210 may also transition from the lower-power operation state 1010 to the higher-power operation state 1020; however, the sensor system 210 may activate or continue executing operations in the higher-power operation(s) state 1020 using the one or more parameter values.
• a parameter value such as a flag value indicating an object is detected or an estimated range to the object
• a computer-vision function in the higher- power operation state 1020 such as a face detection function.
• the sensor system 210 may also transition from the lower-power operation state 1010 to the higher-power operation state 1020; however, the sensor system 210 may activate or
• the sensor system 210 may also detect events in the higher- power operation state 1020 and provide one or more parameter values to a lower-power operation and the sensor system may transition to the lower-power operation state or activate or continue executing operations in the lower-power operation(s) state 1020 using the one or more parameter values.
• FIGS. 11 A, 1 IB and 11C illustrate a process of converting the sensor readings from a plurality of sensor elements to CV features, according to some embodiments.
• FIG. 11A illustrates a group of sensor readings (window 1102) from a plurality of sensor elements of a sensor array unit (e.g., sensor array unit 212 of FIGS. 2A or 2B) that are under consideration for generating a histogram and detecting features.
• a sensor array unit e.g., sensor array unit 212 of FIGS. 2A or 2B
• FIG. 11B illustrates the process of generating the binary threshold values for the center sensor element 1104 for generating an LBP label.
• CV computation hardware 242 of FIG. 2B can include hardware for computing the LBP label.
• the label generated for the center sensor element may be represented by the binary value 1111000.
• an LBP label is generated for each of the nine sensory elements from window 1102.
• Each label may provide an indication of a CV feature from the perspective of the subject sensor element.
• the thresholding to generate the label may be repeated for signals corresponding to multiple subject sensor elements in the sensor array.
• the pixel-level LBP illustrated in FIG. 1 IB can be expanded to include multi-block LBP where the illustrated binary threshold values are generated for a block of one or more subject sensor elements by comparing a value corresponding to the block of one or more subject sensor elements, such a sum of the values associated with the one or more subject sensor elements in the block, to its neighboring sensor element blocks.
• LBP local ternary patterns
• the output is one if the signal corresponding to the neighboring sensor element is greater than the signal corresponding to the subject sensor element plus a threshold, the output is zero if the signal corresponding to the neighboring sensor element is within the threshold compared to the signal corresponding to the subject sensor element, and the output is negative one if the signal corresponding to the neighboring sensor element is less than the signal corresponding to the subject sensor element minus the threshold.
• FIG. llC illustrates a normalized histogram for a window, for example a window representing some subset of sensor elements from a sensor element array, generated from the plurality of labels for each of the sensor elements from the window, for example a sample window stored in hardware scanning window array 238 of FIG. 2B.
• each of the LBP labels for the sensor readings from window 1102 may fall anywhere on a histogram with, for example, 256 slots. So, for example, when comparing a subject sensor element to its eight neighbors, an 8 bit number will be generated meaning that 256 different LBP labels are possible.
• the histogram can represent the number of times each of the given LBP labels were actually generated in the window.
• the generated histogram can be compared to a reference histogram of a face.
• An intersection between the generated histogram and the reference histogram can be computed, and a scalar sum generated from a summation of the intersection. If the scalar sum is greater than a threshold, then, to a given probability, a face is detected within the window.
• the reference histogram and the threshold are generally determined in a training phase using machine learning algorithms on a dataset of, in this example, sample faces and sample non-faces and their LBP histograms.
• the reference histogram and the threshold are determined in the training phase, for the same architecture, they can be programmed in, for example, the microprocessor 216 of FIGS. 2A or 2B, or alternatively the above histogram process may be performed by dedicated hardware for computing a histogram for a given window within an image and determining whether a face, or other object, is present within the window similar to cascade classifier hardware 244 discussed in FIG. 2B above.
• the LBP labels can be used by a cascade classifier for object detection, as discussed in FIG. 2B, instead of or in addition to using the LBP labels for histogram generation.
• FIG. 12 depicts an application environment 1200 for deploying a low-power, single-processor system for handling computer vision hardware control and application program execution, according to an embodiment of the present disclosure.
• a low-power, single-processor system is well-suited for many different types of applications.
• a toy teddy 1210 bear is shown, with a user (i.e., child) 1220 approaching the teddy bear 1210.
• a low-power, single-processor system inside the teddy bear 1210 processes images from a camera (e.g., located inside an eye of the teddy bear) and performs image-based feature detection to detect a human face.
• a camera e.g., located inside an eye of the teddy bear
• the teddy bear 1210 plays a musical tune or begins to speak.
• Other examples of possible actions that may be taken by a toy or other device in response to detecting a human face may include turning on lights, moving a mechanical component, and/or other I/O operations.
• Some non-limiting examples include: (1) people detection, i.e., detection a human figure/body (e.g., as opposed to an animal or an inanimate object), (2) detection of a particular category of animal (e.g., large animals, small pets, etc.), (3) detection of a particular category of object (e.g., a table, a chair, etc.), (4) detection of a certain toy or type of toy (e.g., a "minion" doll), and many others.
• people detection i.e., detection a human figure/body (e.g., as opposed to an animal or an inanimate object)
• detection of a particular category of animal e.g., large animals, small pets, etc.
• detection of a particular category of object e.g., a table, a chair, etc.
• detection of a certain toy or type of toy e.g., a "minion" doll
• teddy bear 1210 is shown to not be connected to a power source via a cable or wire.
• a play toy such as teddy bear 1210 relies on battery power in its normal operations. This is a typical scenario for many toy applications, Internet of Things (IoT) applications, and other I/O device applications. That is, power resources may be quite limited and often are battery-based.
• IoT Internet of Things
• Vision-based detection e.g., to detect a human face
• image processing Utilizing a typical general-purpose processor to carry out software routines and algorithms to implement such image processing would necessitate large power consumption, which is unsuitable for the types of applications where only limited power resources are available for an extended period of time.
• the system is preferably programmable and flexible enough to execute different application programs.
• FIG. 13A is a block diagram of components in a low-power, single-processor system 1300 utilizing multiple software components for handling computer vision hardware control and application program execution, according to an embodiment of the disclosure.
• single-processor system 1300 comprises a vision sensor system 1310, which is communicatively coupled to an I/O device controller 1340.
• Vision sensor system 1310 comprises a visual sensor array unit 1312, peripheral circuitry 1314, a dedicated microprocessor 1320, and memory 1330.
• Vision sensor system 1310 may be similar to the sensor system 210 of FIG. 2A or the sensor system of FIG. 2B. Vision sensor system 1310 receives visual input comprising light in the visible spectrum. The visual input is captured by the visual sensor array unit 1312 in the form of one or more images. Visual sensor array unit 1312 comprises a plurality of pixels arranged in an array. Visual sensor array unit 1312 may be part of a sensor that further comprises physical lenses and other components.
• Peripheral circuitry 1314 operates on image data captured by visual sensor array unit 1312.
• Peripheral circuitry 1314 may include sub-systems such as those illustrated in FIG. 2B, such as ADC 234, 2D integration hardware 236, hardware scanning window array 238, CV computation hardware 242, and cascade classifier hardware 244.
• the subsystems of vision sensor system 1310 may perform computer vision operations, such as LBP and other operations, on the image data, in order to detect features in one or more images captured by visual sensor array unit 1312.
• Some feature detection operation may involve computation of statistics over time (e.g., for motion), amount of areas (e.g., number of pixels) that has changed, etc.
• one type of object detection that can be based on the computer vision features computed within a captured image includes face detection, though other types of object detection may be implemented.
• Results may be outputted and/or stored in memory 1330.
• Dedicated microprocessor 1320 supports a software environment 1322 that includes an operating system (OS), application software, etc.
• Dedicated microprocessor 1320 may be capable of operating in different modes, including, for example, a lower- power mode (e.g., sleep mode, power-down mode, etc.) and a higher-power mode (e.g., awake mode, normal mode, etc.).
• Dedicated microprocessor 1320 serves dual roles: (1) control the operations of the computer vision hardware and (2) execute applications programs to effectuate application-specific I/O operations, e.g., based on results such as the detection of a reference occurrence based on CV operations.
• dedicated microprocessor 1320 utilizes different software components for handling computer vision hardware control and application programs.
• One such software component is a CV hardware controller 1324.
• Software- implemented CV hardware controller 1324 may be built as part of an OS, a driver, and/or an application program executing within the software environment of dedicated microcontroller 1320.
• CV hardware controller 1324 may control one or parameters affecting the operation of the CV computation hardware, such as peripheral circuitry 1314.
• An example of such a parameter is a limited search area parameter, which may comprise one or more values identifying a limited search area within field of view of an image captured by visual sensor array unit 1312, to facilitate a more efficient search for a particular feature, e.g., a human face.
• a limited search area is described in further detail below in association with FIG. 14.
• Other examples of parameters affecting the operation of the CV computation hardware may include parameter that impact computational limits, resolution, speed, efficiency, and the like.
• Such CV computation parameters include object size to detect, target true positive and false alarm rate, sampling density, and preprocessing/conditioning of data. For example, reduced object size may reduce run time, because search for the target feature would take place on a more limited scale.
• parameters that affect the operation of the CV computation hardware include, for example, values for machine learning (ML) models.
• parameters and/or MC model values include thresholds that are to be used by LBP or LTP computation hardware, the weights for generating the scalar weighted averages discussed above with reference to cascade classifier 244 of FIG. 2B, the thresholds that the scalar weighted averages are compared to, the number of stages of the cascade classifier 244.
• Other examples of parameters can include the reference histogram for detecting the presence of a reference object in accordance with the implementation described in FIG. 11C. Additional examples of parameters that relate to ML modeling include parameters for tuning model complexity, training parameters, and positive and negative training parameters, etc.
• CV computation hardware may incorporate machine learning in the detection of features.
• values for ML models may be obtained from training and may be provided by the manufacturer and/or by the user if user training is implemented. More generally, however, dedicated
• microprocessor 1320 controls CV computation hardware, for example, by loading the model, which can include thresholds to be used for CV feature computation.
• the dedicated microprocessor 1320 controls the CV computation hardware by instructing the CV computation hardware, either directly or indirectly (as described in FIG. 2B, where cascade classifier 244 controls CV computation HW 242, but cascade classifier 244 can be instructed by dedicated microprocessor 1320), to perform reference object detection upon receipt of a frame from visual sensor array unit 1312.
• Application program 1326 relies on results of events, e.g., a face-detection event or other event indicating a detection of a reference occurrence, generated based on the operations of the CV computation hardware.
• Application program 1326 also specifies the response that is to occur, in particular the I/O operation that is to be performed in response to the detected event.
• Application program 1326 may communicate with I/O device controller 1340 to effectuate the desired I/O operation.
• the manufacturer of the teddy bear 1210 may specify an application program 1326 and load it into memory 1330, which may include a non-volatile memory such as an EEPROM or flash memory which can either be programmable of physically replaced with a pre-programmed memory that includes the application program.
• Application program 1326 may control the response of teddy bear 1210 upon receipt of the event from the peripheral circuitry 1314.
• teddy bear 1210 plays a musical tune when a human face is detected.
• the musical tune may be a pre-determined digital audio file that may be played by an audio speaker (not shown) coupled to I/O device controller 1340.
• I/O device controller may be an audio controller comprising various components such as a memory, codec, digital-to-analog (D/A) converter, etc.
• Dedicated microprocessor 1320 is dedicated primarily to the tasks of controlling the CV computation hardware and executing the application program(s) that respond to the events generated based on CV operations. By off-loading CV operations to the CV computation hardware and directing the available processing capabilities of dedicated microprocessor 1320 toward control of CV hardware operations and execution of specific application programs affecting I/O operations, the low-power, single-processor system 1300 shown in FIG. 13A is able to balance the need for reduced power consumption along with flexibility to carry out different application programs and support a wide range of I/O operations.
• dedicated microprocessor 1320 is shown in FIG. 13 A as a processor capable of supporting a software environment that includes an operating system (OS) and application programs, in other embodiments, the dedicated microprocessor may comprise simpler circuitry that supports more basic functionality. Just as an example, simple state machines may be used that support functions and/or callbacks. In certain scenarios, e.g., in low-end systems, there may not be support for an operating system (OS). Such simpler circuitry may be utilized to reduce cost and complexity, while still serving the dual tasks of controlling the operations of the computer vision computation hardware as well as controlling the operations of one or more I/O devices, according to various embodiments of the disclosure. [0130] FIG.
• Single-processor system 1350 is a block diagram of components in a single-processor system 1350 utilizing multiple hardware cores for handling computer vision hardware control and application program execution, according to an embodiment of the disclosure.
• Single- processor system 1350 operates in a similar manner as single-processor system 1300 shown in FIG. 13 A, except that in single-processor system 1350, the dual functions of controlling CV computation hardware and executing application programs are performed using two different hardware cores.
• single-processor system 1350 comprises a vision sensor system 1360, which is communicatively coupled to an I/O device controller 1340.
• Vision sensor system 1310 comprises a visual sensor array unit 1312, peripheral circuitry 1314, a dedicated microprocessor 1370, and memory 1330. Most of these components are comparable in their operation to corresponding components shown in FIG.
• dedicated processor 1370 is shown to comprise at least two hardware cores, namely CV hardware controller core 1372 and application processor core 1374.
• CV hardware controller core 1372 is configured to control various operations of the CV computation hardware, including e.g., peripheral circuitry 1314.
• Application processor core 1374 may support a software environment that includes an operating system (OS), application software, etc.
• application processor core 1374 is configured to execute application programs, such an application program installed by a manufacturer of a device, such as a toy bear 1210 (shown in FIG. 12), to perform I/O operations in response to events, e.g., face-detection event, generated based on CV operations.
• OS operating system
• I/O operations I/O operations in response to events, e.g., face-detection event, generated based on CV operations.
• application processor core 1374 and/or CV hardware controller core 1372 may be implemented using simpler circuitry.
• basic state machines that support functions and/or callbacks may be used.
• Such simpler circuitry may be utilized to reduce cost and complexity, while still serving the dual tasks of controlling the operations of the computer vision computation hardware as well as controlling the operations of one or more I/O devices, according to various embodiments of the disclosure.
• FIG. 14 shows an example of a limited search area 1404 specified to streamline feature detection, according to certain embodiments.
• the figure depicts an entire field of view 1402 corresponding to a full image frame.
• a full image frame may be the visual input to the vision sensor system 1310 and 1360 (in FIGs. 13 A and 13B, respectively).
• the field of view of the camera on board the robot may be large enough to capture parts of the ceiling or the sky.
• the application program may restrict object detection (i.e., face- detection) to a limited search area 1404 corresponding to a lower portion of the image. Doing so eliminates computationally- intensive, yet unnecessary, CV operations performed in certain regions of the image.
• Limited search area 1404 may be specified by software-based CV hardware controller 1324 (FIG. 13 A) or CV hardware controller core (FIG. 13B). This is an example of the one or more parameters used by the single-processor system to control the operation of the CV computation hardware.
• the shape, location, and/or size of the limited search area 1404 may differ depending on the application. For example, in certain scenarios, a circular or oval-shaped limited search area may be used.
• the location of the limited search area may be at the center of the entire field of view, in an upper portion of the field of view, in a corner, and the like.
• the size of the limited search area may be varied.
• the shape, location, and/or size of the limited search area may be defined using default settings. Additionally or alternatively, the shape, location, and/or size of the limited search area may be determined based on the inferred or explicit requirements of the application program.
• FIG. 15 shows one example of an I/O device, i.e., an actuator, that may be operated in response to an event detected based on CV operations.
• an I/O device controller 1340 is coupled to an I/O device controller 1340.
• I/O device controller 1340 is an actuator controller that generates control signals for controlling the position/movement of an electrical-to-mechanical actuator 1510.
• actuator controller may be used.
• one type of actuator controller may be a proportional-integral-derivative (PID) controller, which
• Actuator 1510 is mechanically linked to a toy eye that can be moved into an "open eye” position 1520 or "closed eye” position 1522.
• a toy eye or set of toy eyes installed in a toy such as a teddy bear or a doll can be controlled to open or close in response to the detection of events based on CV operations.
• FIG. 15 shows an embodiment in which the I/O device controller 1340 is a distinct component separated from the single-processor vision system 1310, as do FIGS. 13 A and 13B.
• the I/O device controller may be part of the single-processor vision system 1310.
• the I/O device controller 1340 may also be viewed as simply a pin, e.g., a general-purpose input/output (GPIO) pin of the single-processor vision system 1310.
• GPIO general-purpose input/output
• the I/O device controller is to be implemented within the vision sensor system 1310 (for example, within dedication processor 1320 or 1370 with reference to FIGS. 13A and 13B, respectively)
• the programming of the I/O device controller within the processor of the vision sensor can be achieved as described above with reference to the loading of an application program 1326 into memory 1330 in the discussion of FIG. 13A.
• a toy doll 1610 may be installed with a pair of mechanically-adjustable eyes as described.
• the toy doll 1610 may be battery- operated and equipped with a single-processor vision sensor system 1310 that is capable of operating CV computation hardware to generate a face-detection event, execute an application program provided by the manufacturer of the toy doll, and generate a face- detection event.
• the face-detection event may trigger I/O operations to control an actuator to mechanically move the eyes of the doll between the open and closed positions.
• the toy doll 1610 may have its eyes closed initially.
• the toy doll 1610 When user 1620 approaches, and single-processor system within the toy doll 1610 detects the face of user 1620 and, in conjunction with the application program, opens the eyes of the toy doll 1610 and "awakens" in response to the presence of user 1620.
• the eyes of the toy doll 1610 may close when a face in no longer detected, e.g., when user 1620 moves away from the toy doll 1610.
• FIG. 16B shows an example of a door 1630 that unlocks and/or opens automatically based on face-detection.
• Door 1630 may be equipped with a single- processor vision sensor system 1310, in a similar manner as discussed previously.
• the single-processor system may be installed in a door jam or an overhead area of door 1630.
• the single-processor vision sensor system 1310 may be capable of operating CV computation hardware to generate a face-detection event, execute an application program provided by the manufacturer of the door, and generate a face- detection event.
• the face-detection event may trigger I/O operations to control an actuator to mechanically move a locking mechanism and/or a door-opening mechanism that is part of the door 1630.
• the application program may operate to control one or more actuators to (1) unlock door 1630 and (2) open door 1630. These operations may be based on the detection of a human face in an image captured by a camera positioned on the door frame or overhead area of door 1630 and facing the interior of the room.
• the application program may operate differently. For example, upon detection of a human face on the outdoor/exterior side of door 1630, the application program may trigger a user authentication routine, to verify the identity of the user prior to unlocking and/or opening door 1630.
• FIG. 16C shows yet another example, one of a toy robot 1650 that is capable of interacting with a user 1660 based on face-detection.
• Toy robot 1650 may be equipped with a single-processor vision sensor system 1310, in a similar manner as discussed previously.
• the single-processor vision sensor system 1310 may be capable of operating CV computation hardware to generate a face-detection event, execute an application program provided by the manufacturer of the toy robot, and generate a face- detection event.
• the face-detection event may trigger I/O operations to control various operations of the robot to facilitate interaction with user 1660.
• toy robot 1650 may be programmed to perform a "follow the human" task.
• the application program may "track" the location of the detected human face and follow the location of the human face using the mechanically moveable parts of the toy robot 1650. For instance, a finger/hand 1652 of the toy robot may point in the direction of the detected face.
• the single processor may determine the position of the detected face based on the face-detection event, determined based on CV operations. The single processor may control the movement of the finger/hand of the robot based on the determined location of the detected face.
• the finger/hand 1652 of the toy robot may move, via actuators controlled by I/O controllers operating under the direction of the single-processor system 1310 and in conjunction with the application program, to track the location of the face of the user 1660 as it moves relative to the toy robot 1650.
• I/O controllers operating under the direction of the single-processor system 1310 and in conjunction with the application program.
• This and prior examples are presented for illustrative purposes only. Other types of movements and operations may be implemented using the platform presented based on a single- processor system that is capable of controlling CV computation hardware and executing application program(s), to communicate with I/O device controlled s) in conjunction with application program execution.
• FIG. 17 is flow chart illustrating a process 1700 for reacting to scene-based occurrences.
• the process involves receiving, at dedicated computer vision (CV) computation hardware, sensor data from a sensor array comprising a plurality of sensor pixels.
• the process involves computing, at the dedicated CV computation hardware, one or more CV features using readings from neighboring sensor pixels of the sensor array.
• the process involves controlling, using a first processing unit one or more parameters associated with operation of the dedicated CV computation hardware, to affect computation of the one or more CV features.
• the process involves executing, at the first processing unit, one or more application programs.
• the process involves communicating, at the first processing unit and in conjunction with execution of the one or more application programs, with at least one input/output (I/O) device controller, to effectuate an I/O operation in reaction to an event generated based on the one or more computed CV features.
• I/O input/output
• FIG. 18 is a block diagram of internal components of a device 105, such as a toy, IoT device, or other device, that can utilize the techniques and features described herein, according to an embodiment. It should be noted that FIG. 18 is meant only to provide a generalized illustration of various components, any or all of which may be utilized as appropriate. It can be noted that, in some instances, components illustrated by FIG. 18 can be localized to a single physical device and/or distributed among various networked devices, which may be disposed at different physical locations. [0140] The device 105 is shown comprising hardware elements that can be electrically coupled via a bus 1805 (or may otherwise be in communication, as appropriate).
• the hardware elements may include a processing unit(s) 1810 which can include without limitation one or more general-purpose processors, one or more special- purpose processors (such as digital signal processing (DSP) chips, graphics acceleration processors, application specific integrated circuits (ASICs), and/or the like), and/or other processing structure or means.
• the processing unit(s) 1810 may correspond to the main processor 220 of FIG. 2A and/or the second processing unit described in relation to FIG. 4. As shown in FIG. 18, some embodiments may have a separate DSP 1820, depending on desired functionality.
• the device 105 also can include one or more input devices 1870, which can include without limitation a touch screen, a touch pad, microphone, button(s), dial(s), switch(es), and/or the like; and one or more output devices 1816, which can include without limitation a display, light emitting diode (LED), speakers, and/or the like.
• input devices 1870 can include without limitation a touch screen, a touch pad, microphone, button(s), dial(s), switch(es), and/or the like
• output devices 1816 which can include without limitation a display, light emitting diode (LED), speakers, and/or the like.
• LED light emitting diode
• the device 105 might also include a wireless communication interface 1830, which can include without limitation a modem, a network card, an infrared
• the wireless communication interface 1830 may permit data to be exchanged with a network, wireless access points, other computer systems, and/or any other electronic devices described herein.
• the communication can be carried out via one or more wireless communication antenna(s) 1832 that send and/or receive wireless signals 1834.
• the wireless communication interface 1830 can include separate transceivers to communicate with base transceiver stations (e.g., base stations of a cellular network) and/or access point(s). These different data networks can include various network types.
• a Wireless Wide Area Network may be a Code Division Multiple Access (CDMA) network, a Time Division Multiple Access (TDMA) network, a Frequency Division Multiple Access (FDMA) network, an Orthogonal Frequency Division Multiple Access (OFDMA) network, a Single-Carrier Frequency Division Multiple Access (SC-FDMA) network, a WiMax (IEEE 802.16), and so on.
• CDMA Code Division Multiple Access
• TDMA Time Division Multiple Access
• FDMA Frequency Division Multiple Access
• OFDMA Orthogonal Frequency Division Multiple Access
• SC-FDMA Single-Carrier Frequency Division Multiple Access
• WiMax IEEE 802.16
• a CDMA network may implement one or more radio access technologies (RATs) such as cdma2000, Wideband-CDMA (W-CDMA), and so on.
• Cdma2000 includes IS-95, IS-2000, and/or IS-856 standards.
• a TDMA network may implement Global System for Mobile Communications (GSM), Digital Advanced Mobile Phone System (D-AMPS), or some other RAT.
• GSM Global System for Mobile Communications
• D-AMPS Digital Advanced Mobile Phone System
• An OFDMA network may employ LTE, LTE Advanced, and so on.
• LTE, LTE Advanced, GSM, and W- CDMA are described in documents from 3GPP.
• Cdma2000 is described in documents from a consortium named "3rd Generation Partnership Project 2" (3GPP2). 3GPP and 3GPP2 documents are publicly available.
• a Wireless Local Area Network may also be an IEEE 802.1 lx network
• a Wireless Personal Area Network may be a Bluetooth network, an IEEE 802.16x, or some other type of network.
• the techniques described herein may also be used for any combination of WW AN, WLAN and/or WPAN.
• the device 105 can further include sensor(s) 1840.
• sensors can include, without limitation, one or more accelerometer(s), gyroscope(s), camera(s),
• the sensor(s) 1840 may include the sensor system 210 of FIGS. 2A or 2B and/or similar electronic sensors.
• a first processor e.g., microprocessor 216 in FIGS. 2A or 2B
• a second processing unit included in the processing unit(s) 1810 of FIG. 18 (corresponding to the main processor 220 of FIG. 2A).
• a first processing unit of sensor(s) 1840 e.g., microprocessor 216 of sensor system 210 in FIGS.
• the processing unit(s) 1810 can operate in a low power mode, and a first processing unit of sensor(s) 1840 (e.g., microprocessor 216 of sensor system 210 in FIGS. 2A or 2B) is operable to or generate the event to be received by and/or communicate an event to the processing unit(s) 1810 while the processing unit(s) 2010 is/are operating in a low power mode.
• a first processing unit of sensor(s) 1840 e.g., microprocessor 216 of sensor system 210 in FIGS. 2A or 2B
• the processing unit(s) 2010 is/are operating in a low power mode.
• Embodiments of the device may also include a Satellite Positioning System (SPS) receiver 1880 capable of receiving signals 1884 from one or more SPS satellites using an SPS antenna 1882.
• the SPS receiver 1880 can extract a position of the device, using conventional techniques, from satellites of an SPS system, such as a global navigation satellite system (GNSS) (e.g., Global Positioning System (GPS)), Galileo, Glonass, Compass, Quasi-Zenith Satellite System (QZSS) over Japan, Indian Regional Navigational Satellite System (IRNSS) over India, Beidou over China, and/or the like.
• GNSS global navigation satellite system
• GPS Global Positioning System
• Galileo Galileo
• Glonass Galileo
• Glonass Galileo
• Glonass Compass
• QZSS Quasi-Zenith Satellite System
• IRNSS Indian Regional Navigational Satellite System
• Beidou Beidou over China
• the SPS receiver 1880 can be used various augmentation systems (e.g., an Satellite Based Augmentation System (SBAS)) that may be associated with or otherwise enabled for use with one or more global and/or regional navigation satellite systems.
• an SBAS may include an augmentation system(s) that provides integrity information, differential corrections, etc., such as, e.g., Wide Area Augmentation System (WAAS), European Geostationary Navigation Overlay Service (EGNOS), Multi -functional Satellite Augmentation System (MSAS), GPS Aided Geo Augmented Navigation or GPS and Geo Augmented Navigation system (GAGAN), and/or the like.
• WAAS Wide Area Augmentation System
• GNOS European Geostationary Navigation Overlay Service
• MSAS Multi -functional Satellite Augmentation System
• GPS Aided Geo Augmented Navigation or GPS and Geo Augmented Navigation system (GAGAN) GPS Aided Geo Augmented Navigation or GPS and Geo Augmented Navigation system (GAGAN), and/or the like.
• SPS may include any combination of one or more global and/
• the device 105 may further include and/or be in communication with a memory 1860.
• the memory 1860 can include, without limitation, local and/or network accessible storage, a disk drive, a drive array, an optical storage device, a solid-state storage device, such as a random access memory (“RAM”), and/or a read-only memory (“ROM”), which can be programmable, flash-updateable, and/or the like.
• RAM random access memory
• ROM read-only memory
• Such storage devices may be configured to implement any appropriate data stores, including without limitation, various file systems, database structures, and/or the like.
• the memory 218 of FIG. 2A which can include any of the memory types previously listed, may be included in the memory 1860 or may be distinct from memory 1860, depending on desired functionality.
• the memory 1860 of the device 105 also can comprise software elements (not shown), including an operating system, device drivers, executable libraries, and/or other code embedded in a computer-readable medium, such as one or more application programs, which may comprise computer programs provided by various embodiments, and/or may be designed to implement methods, and/or configure systems, provided by other embodiments, as described herein.
• application programs which may comprise computer programs provided by various embodiments, and/or may be designed to implement methods, and/or configure systems, provided by other embodiments, as described herein.
• code and/or instructions can be used to configure and/or adapt a general purpose computer (or other device) to perform one or more operations in accordance with the described methods.
• components that can include memory can include non-transitory machine-readable media.
• machine-readable medium and “computer-readable medium” as used herein, refer to any storage medium that participates in providing data that causes a machine to operate in a specific fashion.
• various machine-readable media might be involved in providing instructions/code to processing units and/or other device(s) for execution. Additionally or alternatively, the machine-readable media might be used to store and/or carry such instructions/code.
• a computer- readable medium is a physical and/or tangible storage medium. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media.
• Computer-readable media include, for example, magnetic and/or optical media, punchcards, papertape, any other physical medium with patterns of holes, a RAM, a PROM, EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read instructions and/or code.
• a special purpose computer or a similar special purpose electronic computing device is capable of manipulating or transforming signals, typically represented as physical electronic, electrical, or magnetic quantities within memories, registers, or other information storage devices, transmission devices, or display devices of the special purpose computer or similar special purpose electronic computing device.
• the term "at least one of if used to associate a list, such as A, B, or C, can be interpreted to mean any combination of A, B, and/or C, such as A, AB, AA, AAB, AABBCCC, etc.

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