PATENT DOCUMENT

Publication Number: US-11237671-B1
Application Number: US-202016903564-A
Country: US
Kind Code: B1

Title: Temporal filter touch detection

Abstract:
Detecting a touch includes determining, from first raw touch data, an estimated touch type for a first plurality of frames, obtaining second raw touch data comprising a probability that a touch has occurred for each of a second plurality of frames, applying the selected filter to the additional raw data to obtain processed data, and detecting whether a touch has occurred for a particular frame based on the processed data.

Claims:
The invention claimed is: 
     
       1. A non-transitory computer readable medium comprising computer readable code executable by one or more processors to:
 determine, from first raw touch data, an estimated touch type for a first plurality of frames; 
 obtain second raw touch data comprising a probability that a touch has occurred for each of a second plurality of frames; 
 select a filter based on the estimated touch type; 
 apply the selected filter to the second raw data to obtain processed data; 
 detect whether a touch has occurred for a particular frame based on the processed data. 
 
     
     
       2. The non-transitory computer readable medium of  claim 1 , wherein determining the estimated touch type comprises obtaining a probability that a touch has occurred for each of the first plurality of frames. 
     
     
       3. The non-transitory computer readable medium of  claim 1 , wherein the touch type comprises one selected from a group consisting of a click and a drag. 
     
     
       4. The non-transitory computer readable medium of  claim 3 , wherein the computer readable code to select the filter based on the estimated touch type comprises computer readable code to select a high pass filter if the determined estimated touch type is a click. 
     
     
       5. The non-transitory computer readable medium of  claim 3 , wherein the computer readable code to select the filter based on the estimated touch type comprises computer readable code to select a low pass filter if the determined estimated touch type is a drag. 
     
     
       6. The non-transitory computer readable medium of  claim 1 , further comprising computer readable code to select a threshold probability value based on the estimated touch type, wherein the computer readable code to detect whether a touch has occurred for a particular frame comprises determining that the processed data for the particular frame satisfies the selected threshold value. 
     
     
       7. The non-transitory computer readable medium of  claim 1 , wherein the touch type is associated with a touch event, and wherein the touch event occurs between a fingertip and a surface. 
     
     
       8. A system for detecting a touch, comprising:
 one or more processors; and 
 one or more storage devices comprising computer readable code executable by the one or more processors to: 
 determine, from first raw touch data, an estimated touch type for a first plurality of frames; 
 obtain second raw touch data comprising a probability that a touch has occurred for each of a second plurality of frames; 
 select a filter based on the estimated touch type; 
 apply the selected filter to the second raw data to obtain processed data; 
 detect whether a touch has occurred for a particular frame based on the processed data. 
 
     
     
       9. The system of  claim 8 , wherein determining the estimated touch type comprises obtaining a probability that a touch has occurred for each of the first plurality of frames. 
     
     
       10. The system of  claim 8 , wherein the touch type comprises one selected from a group consisting of a click and a drag. 
     
     
       11. The system of  claim 10 , wherein the computer readable code to select the filter based on the estimated touch type comprises computer readable code to select a high pass filter if the determined estimated touch type is a click. 
     
     
       12. The system of  claim 10 , wherein the computer readable code to select the filter based on the estimated touch type comprises computer readable code to select a low pass filter if the determined estimated touch type is a drag. 
     
     
       13. The system of  claim 8 , further comprising computer readable code to select a threshold probability value based on the estimated touch type, wherein the computer readable code to detect whether a touch has occurred for a particular frame comprises determining that the processed data for the particular frame satisfies the selected threshold value. 
     
     
       14. The system of  claim 8 , wherein the touch type is associated with a touch event, and wherein the touch event occurs between a fingertip and a surface. 
     
     
       15. A method for detecting a touch, comprising:
 determining, from first raw touch data, an estimated touch type for a first plurality of frames; 
 obtaining second raw touch data comprising a probability that a touch has occurred for each of a second plurality of frames; 
 selecting a filter based on the estimated touch type; 
 applying the selected filter to the second raw data to obtain processed data; 
 detecting whether a touch has occurred for a particular frame based on the processed data. 
 
     
     
       16. The method of  claim 15 , wherein determining the estimated touch type comprises obtaining a probability that a touch has occurred for each of the first plurality of frames. 
     
     
       17. The method of  claim 15 , wherein the touch type comprises one selected from a group consisting of a click and a drag. 
     
     
       18. The method of  claim 17 , wherein selecting the filter based on the estimated touch type comprises selecting a high pass filter if the determined estimated touch type is a click. 
     
     
       19. The method of  claim 17 , wherein selecting the filter based on the estimated touch type comprises selecting a low pass filter if the determined estimated touch type is a drag. 
     
     
       20. The method of  claim 15 , further comprising selecting a threshold probability value based on the estimated touch type, wherein detecting whether a touch has occurred for a particular frame comprises determining that the processed data for the particular frame satisfies the selected threshold value.

Description:
BACKGROUND 
     This disclosure relates generally to the field of touch detection, and more specifically to the field of utilizing a temporal filter for vision-based touch detection. 
     Today&#39;s electronic devices provide users with many ways to interact with the world around them. For example, users may interact with electronic devices using virtual or physical keyboards, mice, trackballs, joysticks, touch screens, and the like. One way that users often interact with digital information on their device is through a touch screen interface. Touch screen interfaces allow a user to interact with a display surface using a finger, stylus, or other object. A touch sensor recognizes the area touched and provides a response to a user. 
     With the rise of mixed reality environments, users often provide input by additional means in order to enable virtual objects to interact with real objects. As an example, a user may touch a real object in order to interact with the real object in a mixed reality manner. However, real objects often do not include touch sensors which are traditionally utilized to detect touch from a user. What is needed is an improved manner to detect touch without a touch sensor-enabled surface. 
     SUMMARY 
     In one embodiment, a method for touch detection is described. The method may include determining, from first raw touch data, an estimated touch type for a first plurality of frames, obtaining second raw touch data comprising a probability that a touch has occurred for each of a second plurality of frames, applying the selected filter to the additional raw data to obtain processed data, and detecting whether a touch has occurred for a particular frame based on the processed data. 
     In another embodiment, the method may be embodied in computer executable program code and stored in a non-transitory storage device. In yet another embodiment, the method may be implemented in an electronic device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows, in block diagram form, a simplified system diagram according to one or more embodiments. 
         FIG. 2A  shows, an example system setup in which touch may be detected, according to one or more embodiments. 
         FIG. 2B  shows example touch data obtained from a vision-based touch detection technique, according to one or more embodiments. 
         FIG. 3  shows, flow chart form, an example technique for temporally filtering touch data, in accordance with one or more embodiments. 
         FIG. 4  shows, in flow chart form, an example technique for dynamically modifying a touch detection technique, according to one or more embodiments. 
         FIG. 5  shows, in block diagram form, a simplified multifunctional device according to one or more embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure is directed to systems, methods, and computer readable media for detecting touch in a physical environment. In general, techniques are disclosed to provide a refined technique for identifying when a user touches a surface in a physical environment using vision-based techniques. Specifically, touch data, typically indicating a likelihood of a touch at particular moments over time, may be processed by applying a particular filter, wherein the type of filter applied is based on a determined type of touch being detected over time. 
     According to one or more embodiments, raw touch data is obtained for an initial series of frames. The raw touch data may indicate a likelihood of a touch for each frame or a hover distance of a fingertip to a touching surface for each frame. The raw touch data may be analyzed to determine a type of touch, such as a click or a drag or a swipe. For purposes of this disclosure, a click describes an acute touch action, whereas a drag describes a sustained touch action. If a click action is detected in the initial series of frames, then for touch data from future frames, a particular filter is selected based on the touch type. In one or more embodiments, a high pass filter is utilized for a clicking touch type, and a low pass filter is utilized for a dragging touch type. The touch data may be processed utilizing the filter, and the processed touch data may be utilized to detect a touch. The processed data may be utilized to detect a touch. The touch may then be detected in any number of ways from the filtered data. 
     The raw touch data (e.g. touch probability or hover distance) could be obtained by a depth based touch detection. For example, depth images of a fingertip touching a real surface may be captured. A fingertip position may be detected in a depth image, and raw touch data may be determined for the fingertip position based on a finger patch containing depth pixels around the detected fingertip position. In one or more embodiments, raw touch data may be determined from the depth pixels by determining a surface in the scene, for example using random sample consensus (RANSAC) plane estimation, and estimating distances to the determined plane for each pixel in the finger patch. Then, distance estimation or classification may be performed to estimate a hover distance, or a likelihood of a touch, based on the distances to the determined plane. 
     In one embodiment, a touch event may be determined by applying a threshold to the raw touch data (e.g. touch probability or hover distance) from one frame. The touch event may indicate the first frame of a series of touching surface. 
     A break touch event can be determined by applying a break touch threshold to raw touch data (e.g., touch probability or hover distance) from one frame. The break touch event may indicate the last frame of a series of frames in which a surface is being touched. A click action may be determined when the detected touch event and break touch events are at the same position, or positions within a predetermined distance. A drag action may be determined when the detected touch event and break touch events are at different positions, or a distance apart that satisfies a predetermined threshold. The positions of touch event and break touch event could be determined in the real surface coordinate, user coordinate system or any other coordinate system. The velocity of fingertip could be computed based on fingertip position across different frames, which could be used to further distinguish between a drag action and a swipe action. 
     In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed concepts. As part of this description, some of this disclosure&#39;s drawings represent structures and devices in block diagram form in order to avoid obscuring the novel aspects of the disclosed embodiments. In this context, it should be understood that references to numbered drawing elements without associated identifiers (e.g.,  100 ) refer to all instances of the drawing element with identifiers (e.g.,  100   a  and  100   b ). Further, as part of this description, some of this disclosure&#39;s drawings may be provided in the form of a flow diagram. The boxes in any particular flow diagram may be presented in a particular order. However, it should be understood that the particular flow of any flow diagram is used only to exemplify one embodiment. In other embodiments, any of the various components depicted in the flow diagram may be deleted, or the components may be performed in a different order, or even concurrently. In addition, other embodiments may include additional steps not depicted as part of the flow diagram. The language used in this disclosure has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the disclosed subject matter. Reference in this disclosure to “one embodiment” or to “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment, and multiple references to “one embodiment” or to “an embodiment” should not be understood as necessarily all referring to the same embodiment or to different embodiments. 
     It should be appreciated that in the development of any actual implementation (as in any development project), numerous decisions must be made to achieve the developers&#39; specific goals (e.g., compliance with system and business-related constraints), and that these goals will vary from one implementation to another. It will also be appreciated that such development efforts might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art of image capture having the benefit of this disclosure. 
     For purposes of this disclosure, the term “lens” refers to a lens assembly, which could include multiple lenses. In one or more embodiments, the lens may be moved to various positions to capture images with different points of focus. Further in one or more embodiments, the lens may refer to any kind of lens, such as a telescopic lens or a wide angle lens. As such, the term lens can mean a single optical element or multiple elements configured into a stack or other arrangement. 
     For purposes of this disclosure, the term “camera system” refers to one or more lens assemblies along with the one or more sensor elements and other circuitry utilized to capture an image. For purposes of this disclosure, the “camera” may include more than one camera system, such as a stereo camera system, multi-camera system, or a camera system capable of sensing the depth of the captured scene. 
     A physical environment refers to a physical world that people can sense and/or interact with without aid of electronic systems. Physical environments, such as a physical park, include physical articles, such as physical trees, physical buildings, and physical people. People can directly sense and/or interact with the physical environment, such as through sight, touch, hearing, taste, and smell. 
     In contrast, a computer-generated reality (CGR) environment refers to a wholly or partially simulated environment that people sense and/or interact with via an electronic system. In CGR, a subset of a person&#39;s physical motions, or representations thereof, are tracked, and, in response, one or more characteristics of one or more virtual objects simulated in the CGR environment are adjusted in a manner that comports with at least one law of physics. For example, a CGR system may detect a person&#39;s head turning and, in response, adjust graphical content and an acoustic field presented to the person in a manner similar to how such views and sounds would change in a physical environment. In some situations (e.g., for accessibility reasons), adjustments to characteristic(s) of virtual object(s) in a CGR environment may be made in response to representations of physical motions (e.g., vocal commands). 
     A person may sense and/or interact with a CGR object using any one of their senses, including sight, sound, touch, taste, and smell. For example, a person may sense and/or interact with audio objects that create 3D or spatial audio environment that provides the perception of point audio sources in 3D space. In another example, audio objects may enable audio transparency, which selectively incorporates ambient sounds from the physical environment with or without computer-generated audio. In some CGR environments, a person may sense and/or interact only with audio objects. 
     Examples of CGR include virtual reality and mixed reality. A virtual reality (VR) environment refers to a simulated environment that is designed to be based entirely on computer-generated sensory inputs for one or more senses, A VR environment comprises a plurality of virtual objects with which a person may sense and/or interact. For example, computer-generated imagery of trees, buildings, and avatars representing people are examples of virtual objects. A person may sense and/or interact with virtual objects in the VR environment through a simulation of the person&#39;s presence within the computer-generated environment, and/or through a simulation of a subset of the person&#39;s physical movements within the computer-generated environment. 
     In contrast to a VR environment, which is designed to be based entirely on computer-generated sensory inputs, a mixed reality (MR) environment refers to a simulated environment that is designed to incorporate sensory inputs from the physical environment, or a representation thereof, in addition to including computer-generated sensory inputs (e.g., virtual objects). On a virtuality continuum, a mixed reality environment is anywhere between, but not including, a wholly physical environment at one end and virtual reality environment at the other end. 
     In some MR environments, computer-generated sensory inputs may respond to changes in sensory inputs from the physical environment. Also, some electronic systems for presenting an MR environment may track location and/or orientation with respect to the physical environment to enable virtual objects to interact with real objects (that is, physical articles from the physical environment or representations thereof). For example, a system may account for movements so that a virtual tree appears stationery with respect to the physical ground. 
     Examples of mixed realities include augmented reality and augmented virtuality. An augmented reality (AR) environment refers to a simulated environment in which one or more virtual objects are superimposed over a physical environment, or a representation thereof. For example, an electronic system for presenting an AR environment may have a transparent or translucent display through which a person may directly view the physical environment. The system may be configured to present virtual objects on the transparent or translucent display, so that a person, using the system, perceives the virtual objects superimposed over the physical environment. Alternatively, a system may have an opaque display and one or more imaging sensors that capture images or video of the physical environment, which are representations of the physical environment. The system composites the images or video with virtual objects, and presents the composition on the opaque display. A person, using the system, indirectly views the physical environment by way of the images or video of the physical environment, and perceives the virtual objects superimposed over the physical environment. As used herein, a video of the physical environment shown on an opaque display is called “pass-through video,” meaning a system uses one or more image sensor(s) to capture images of the physical environment, and uses those images in presenting the AR environment on the opaque display. Further alternatively, a system may have a projection system that projects virtual objects into the physical environment, for example, as a hologram or on a physical surface, so that a person, using the system, perceives the virtual objects superimposed over the physical environment. 
     An augmented reality environment also refers to a simulated environment in which a representation of a physical environment is transformed by computer-generated sensory information. For example, in providing pass-through video, a system may transform one or more sensor images to impose a select perspective (e.g., viewpoint) different than the perspective captured by the imaging sensors. As another example, a representation of a physical environment may be transformed by graphically modifying (e.g., enlarging) portions thereof, such that the modified portion may be representative but not photorealistic versions of the originally captured images. As a further example, a representation of a physical environment may be transformed by graphically eliminating or obfuscating portions thereof. 
     An augmented virtuality (AV) environment refers to a simulated environment in which a virtual or computer generated environment incorporates one or more sensory inputs from the physical environment. The sensory inputs may be representations of one or more characteristics of the physical environment. For example, an AV park may have virtual trees and virtual buildings, but people with faces photorealistically reproduced from images taken of physical people. As another example, a virtual object may adopt a shape or color of a physical article imaged by one or more imaging sensors. As a further example, a virtual object may adopt shadows consistent with the position of the sun in the physical environment. 
     Referring to  FIG. 1 , a simplified block diagram of an electronic device  100  is depicted, in accordance with one or more embodiments of the disclosure. Electronic device  100  may be part of a multifunctional device, such as a mobile phone, tablet computer, personal digital assistant, portable music/video player, wearable device, base station, laptop computer, desktop computer, network device, or any other electronic device.  FIG. 1  shows, in block diagram form, an overall view of a system diagram capable of providing touch detection using visual means. Although not shown, electronic device  100  may be connected to additional devices capable of providing similar or additional functionality across a network, a wired connection, a Bluetooth or other short range connection, among others. 
     Electronic Device  100  may include processor, such as a central processing unit (CPU)  120 . Processor  120  may be a system-on-chip such as those found in mobile devices and include one or more dedicated graphics processing units (GPUs). Further processor  120  may include multiple processors of the same or different type. Electronic Device  100  may also include a memory  130 . Memory  130  may each include one or more different types of memory, which may be used for performing device functions in conjunction with processor  120 . For example, memory  130  may include cache, ROM, RAM, or any kind of transitory or non-transitory computer readable storage medium capable of storing computer readable code. Memory  130  may store various programming modules for execution by processor  120 , including touch detection module  135 . Electronic device  100  may also include storage  140 . Storage  140  may include one more non-transitory computer-readable storage mediums including, for example, magnetic disks (fixed, floppy, and removable) and tape, optical media such as CD-ROMs and digital video disks (DVDs), and semiconductor memory devices such as Electrically Programmable Read-Only Memory (EPROM), and Electrically Erasable Programmable Read-Only Memory (EEPROM). Storage  140  may include historic touch data  145 . It should be understood that according to one or more embodiments, the touch detection module  135  and the historic touch data  145  may be stored or hosted in different locations within electronic device  100 . Further, in one or more embodiments, the touch detection module  135  and the historic touch data  145  may be stored in alternative or additional locations, such as network devices operatively connected to electronic device  100  across a network, as described above. 
     In one or more embodiments, electronic device  100  may include other components utilized for vision-based touch detection, such as one or more cameras  105  and/or other sensors such as depth sensors  110 . In one or more embodiments, each of the one or more cameras  105  may be a traditional RGB camera, or a depth camera. Further, cameras  105  may include a stereo- or other multi-camera system, a time-of-flight camera system, or the like which capture images from which depth information of a scene may be determined. 
     In one or more embodiments, electronic device  100  may allow a user to interact with CGR environments. There are many different types of electronic systems that enable a person to sense and/or interact with various CGR environments. Examples include head mounted systems, projection-based systems, heads-up displays (HUDs), vehicle windshields having integrated display capability, windows having integrated display capability, displays formed as lenses designed to be placed on a person&#39;s eyes (e.g., similar to contact lenses), headphones/earphones, speaker arrays, input systems (e.g., wearable or handheld controllers with or without haptic feedback), smartphones, tablets, and desktop/laptop computers. A head mounted system may have one or more speaker(s) and an integrated opaque display. Alternatively, a head mounted system may be configured to accept an external opaque display (e.g., a smartphone). The head mounted system may incorporate one or more imaging sensors to capture images or video of the physical environment, and/or one or more microphones to capture audio of the physical environment. Rather than an opaque display, a head mounted system may have a transparent or translucent display. The transparent or translucent display may have a medium through which light representative of images is directed to a person&#39;s eyes. 
     In one or more embodiments, touch detection module  135  may determine an estimation of whether a touch event has occurred. A touch event may indicate a likelihood that contact has been made between a touching object (such as a finger or fingertip) and a surface. The touch detection module  135  may determine when a touch event occurs, for example, by obtaining depth information for a touching object and a surface. As an example, the touch detection module  135  may receive or obtain depth information from the camera  105 , the depth sensor  110 , or other sensor, and determine, based on the signal, an estimation that a touch event has occurred. In one or more embodiments, the estimation may be made based on a number of factors, such as by utilizing a predetermined model of a finger or other touching object, utilizing a predetermined or dynamically determined threshold estimation value for determining a touch, etc. Touch detection module  135  may also estimate a distance between a touching object and a surface. 
     In one or more embodiments, the touch detection module  135  utilizes historic information to determine a type of touch that has recently been detected in order to determine how to process the touch data. As described above, the historic touch data  145  may be stored in long-term or short-term memory. The historic touch data  145  may indicate a likelihood of a touch for a particular frame, according to one or more embodiments. In one or more embodiments, the touch detection module  135  may determine an initial touch type. That is, a touch type may be determined for a first set of frames prior to a particular filter being selected. In one or more embodiments, a default filter or no filter may be applied to the touch data from the initial frames. 
     Although electronic device  100  is depicted as comprising the numerous components described above, in one or more embodiments, the various components may be distributed across multiple devices. Particularly, in one or more embodiments, one or more of the touch detection module  135 , and historic touch data  145  may be distributed differently across the electronic device  100  or elsewhere in additional systems which may be communicably coupled to the electronic device  100 . Thus, the electronic device  100  may not be needed to perform one or more techniques described herein, according to one or more embodiments. Accordingly, although certain calls and transmissions are described herein with respect to the particular systems as depicted, in one or more embodiments, the various calls and transmissions may be made differently directed based on the differently distributed functionality. Further, additional components may be used, some combination of the functionality of any of the components may be combined. 
       FIG. 2A  shows, an example system setup  200  in which touch may be detected, according to one or more embodiments. The system includes electronic device  100 . Shown on electronic device  100  are camera  105  and/or depth sensor  110 . In one or more embodiments, the electronic device (e.g., camera  105  of electronic device  100 ) captures an image of an environment including a touch surface  225  and a touching object  205 . In order to determine a likelihood of a touch between the touching object  205  and the target surface  225 , the touching object  205  and the target surface  225  may be captured by the camera  105  within a view area  240  of the camera  105 . In one or more embodiments, the surface  225  may be any kind of surface on which the touch may be detected. The surface  225  may be a flat surface, or may be a curved or irregular surface. According to one or more embodiments, a model of the surface may be registered with the electronic device  100  such that depth information may be utilized to determine a likelihood of a touch based on depth or visual information. In alternative embodiments, the electronic device  100  may determine a likelihood of a touch between the touching object  205  and the surface  225  without relying on a model of the touching object. 
       FIG. 2B  shows example touch data obtained from a vision-based touch detection technique, according to one or more embodiments. Specifically,  FIG. 2B  shows two example probability charts, one for a dragging touch type, and one for a clicking touch type. According to one or more embodiments, raw touch data may include a probability of a touch for each frame. The probability may be determined based on depth information, such as that obtained from a stereocamera system, a depth sensor, a depth camera, a time-of-flight sensor, and the like. 
     The raw touch data, e.g. touch probability or hover distance, could be obtained by depth based touch detection. For example, depth images of a fingertip touching a real surface may be captured. In one or more embodiments, the touch detection module may first detect a fingertip position in a depth image and determine raw touch data for the fingertip based on a finger patch (for example, a portion of the image depicting the tip of the finger) containing depth pixels around the detected fingertip position. In one or more embodiments, determining raw touch data from the depth pixels includes first determining a surface based on RANSAC plane estimation, and estimating a distance to the determined plane for each pixel in the finger patch. Then distance regression may be performed to predict a hover distance. Alternatively, binary classification may be performed to predict a likelihood of a touch based on the finger patch of distances to the determined plane. 
     Probability chart  250  depicts a chart of a probability of a touch  260 A for each frame  270 A. As shown during time frame  295 A, an estimation  290 A for each frame is plotted form frames 5-15. Also depicted is a threshold probability  280 A which is utilized to determine whether the frame should be considered a touch. That is, if a probability of a touch satisfies a predetermined threshold, then a touch is determined to have occurred in a particular frame. In one or more embodiments, the predetermined threshold  280 A may be a predetermined value. In one or more embodiments, the probability threshold may be dynamically modified, for example based on learned behavior of a user (e.g., a user may benefit from a lower threshold or a higher threshold based on touch behavior). As another example, the probability threshold  280 A may be dynamically modified based on a touch type. For example, as is described herein, a touch type may be determined for a series of frames. Thereafter, the probability threshold value may be modified based on an ongoing touch type. As an example, a click touch type may require or may benefit from a different touch threshold than a draft touch type. As shown, a touch is detected in frames 5-11, and then a touch is not detected in frames 12-13, and a touch is detected again at 14. As such, a drag touch type may be detected based on the sustained touch between frames 5-11. 
     In one embodiment, a touch event can be determined by applying a threshold to raw touch data (e.g. touch probability or hover distance) from one frame. The touch event may indicate the first frame of a series of frames in which the touching object is touching the surface. For example, in  295 B, a touch event is detected at frame  11 . A break touch event can be determined by applying another threshold on raw touch data (e.g., touch probability or hover distance) from one frame. The break touch event may indicate the last frame of a series in which the touch object is touching the surface. For example in  FIG. 295B , a break touch event is detected at frame  12 . A click action can be determined if the both the detected touch event and the break touch event are at the same position or positions within a predetermined distance. A drag action may be determined if the detected touch event and break touch events are detected at different positions. The positions of make touch and break touch events could be in the real surface coordinate, user coordinate system or any other coordinate system. The positions of make touch and break touch events may be detected by estimating fingertip positions in an image captured by a camera sensor. The velocity of fingertip could be computed based on position across different frames, which could be used to further distinguish between a drag action and a swipe action. 
     A click action may also be determined if the number of frames between the detected touch event and the break touch event is small. A drag action may also be determined if the number of frames between the detected touch event and break touch events is greater than a predetermined threshold. 
     Similarly, probability chart  275  depicts a chart of a probability of a touch  260 B for each frame  270 B. As shown during time frame  295 B, an estimation  290 B for each frame is plotted form frames 5-15. Also depicted is a threshold probability  280 B which is utilized to determine whether the frame should be considered a touch. That is, if a probability of a touch satisfies a predetermined threshold, then a touch is determined to have occurred in a particular frame. As shown, a touch is detected at frame  5 , then a touch detection is not detected at frames 6-10. Then, a touch may be detected again at frames 11-12, and then a touch is not detected at frames 13-14. As such, a click touch type may be detected based on the short number of consecutive frames indicating a touch is determined. The touch type may be determined based on a threshold number of frames indicating a touch (i.e., a drag). That threshold number may also change based on the velocity of a fingertip. 
       FIG. 3  shows, flow chart form, an example technique for temporally filtering touch data, in accordance with one or more embodiments. For purposes of explanation, the following steps will be described in the context of  FIG. 1 . However, it should be understood that the various actions may be taken by alternate components. In addition, the various actions may be performed in a different order. Further, some actions may be performed simultaneously, and some may not be required, or others may be added. 
     The flowchart begins at  305  where the electronic device  100  obtains a series of frames capturing a touch event. As described above, the series of frames may contain depth information and/or image information from which depth information may be determined. The touch event may include a contact or a potential contact between a touching object and a surface. As such, the touch event may or may not include a touch and, according to one or more embodiments, the series of frames may simply capture a touching object, such as a finger, and a surface. That is the touching object may or may not actually be touching anything. Rather, the “touching” object may simply be the object for which a touch is estimated. In one or more embodiments, the number of frames in the series of frames may be a predetermined value, or may be modified, for example, based on user input, or may be modified dynamically, such as in a manner described below with respect to  FIG. 4 . 
     The flowchart continues at  310  where the touch detection module  135  determines a touch probability of each frame of the series of frames. In one or more embodiment, the touch probability comprises raw touch data from which a touch may be estimated. As an example, based on a determined depth of a touching object and a depth of a surface near the touching object. The touch detection module  135  may then determine an estimated probability of a touch based on the depth information. 
     At  315 , the touch detection module  135  applies a threshold touch value to the touch probabilities to identify touches in the touch data. In one or more embodiments, the threshold value is applied to the probability data to label a frame as either a touch frame or not a touch frame. As an example, if a probability value for a frame is 70% likely to be a touch, and the threshold value is 50%, then the frame may be determined to be a touch frame. Similarly, if the threshold value is 80%, then the frame will be determined to not include a touch. In one or more embodiments, the threshold value may be predetermined, or many vary based on various parameters, such as touch type (e.g., the threshold value may be modified if a particular touch type is detected), human behavior (e.g., the threshold may be modified based on the behavior of the user utilizing the visual touch technique), context (e.g., the threshold may be modified based on contextual information that may affect the ability to detect a likelihood of a touch, such as environmental factors or factors related to the surface and/or the touch object). 
     At  320  where the touch detection module  135  determines a touch type based on the identified touches, as described above. The flowchart continues at  325  where the touch detection module  135  receives additional series of frames capturing an additional touch event. In one or more embodiments, the additional series of frames may also include a predetermined number of frames, or may be modified over time. That is, the additional series of frames may include the same number of frames as obtained at  305 , or may include a different number of frames. Then, at  330  the touch detection module determines a touch probability of each frame of the additional series of frames to obtain touch data, similar to that described above with respect to  310 . 
     At  335 , the touch detection module selects a filter by which to process the touch data based on the determined touch type. In one or more embodiments, the type of filter may be a high pass filter or a low pass filter. A high pass filter may be utilized for a click touch type. In one or more embodiments, applying a high pass filter to a click touch type reduces the likelihood that click data will be lost as noise. Further, applying a low pass filter to a drag touch type removes the noise and provides a smoothing filter to the touch data. In one or more embodiments, the high pass filter may require more processing resources than a low pass filter. As such, reserving processing resources for click touch type actions may allow the touch detection module  135  to optimize or improve resource consumption of the electronic device  100 . At  340 , the selected filter is applied to the touch data. The flowchart concludes at  345  where the touch detection module performs touch detection on the processed data. 
       FIG. 4  shows, in flow chart form, an example technique for dynamically modifying a touch detection technique, according to one or more embodiments. In one or more embodiments, the performance of the touch detection may be optimized or improved by modifying the window of frames from which a touch type is determined, and therefore a filter is determined. 
     The flowchart begins at  405  where a window size is selected. The window size indicates a number of frames to be utilized to determine a click type. The window size may be any number of frames, such as 5 frames, 10 frames, or the like. In one or more embodiments, the window size may be selected as a default window size, or may be determined on other factors, such as prior touch data, contextual data, user preference, power savings, and the like. 
     The flowchart continues at  410  and the electronic device receives or obtains a next plurality of frames of the selected window size (e.g., the window size selected at  405 ). While the flowchart uses the term “next” plurality of frames, it could refer to an initial plurality of frames, according to one or more embodiments. In one or more embodiments, the plurality of frames comprise depth information or other information from which depth may be determined, and may capture a scene including a touching object  205  and a target surface  225 . 
     At  415 , the touch detection module  135  determines a touch type for the next plurality of frames. Note that the “next” plurality of frames here refers to the plurality of frames received at  410 . As described above, a touch type may be a click touch type or a drag touch type, according to one or more embodiments, where a click indicates a tap by a touching object on a surface and a drag indicates a sustained movement by a touching object on a surface. The touch type may be determined in any number of ways, as described above. 
     At  420 , a determination is made whether a new touch type is detected. That is, a determination is made regarding whether a different touch type is detected, from a touch type that was previously detected from a previous window (e.g. a previous set of frames), if one was previously detected. If at  420 , a new touch type is detected, then the flowchart continues at  430  and the touch detection module  135  modifies the processing format for the touch data to use a new filter (e.g., the filter associated with the touch type) for touch detection. As described above, a high pass filter may be utilized for a click touch type, where a low pass filter may be used for a drag touch type. Then the flowchart continues at  410 , and the next plurality of frames of the selected window size is received. 
     Returning to  420 , if a determination is made that a new touch type is not detected, then the flowchart continues at  435  and a determination is made regarding whether the same touch type has been determined over a threshold time period or a threshold number of cycles. That is, if the same touch type is determined repeatedly over a determined period of time, or a number of cycles (e.g., a number of determinations of touch type), then the number of frames may increase. That is, in one or more embodiments, if a particular touch type is repeatedly identified, then the touch detection module  135  may increase the number of frames utilized to determine a touch type and, therefore, a filter type that should be used to process the raw touch data. 
     If at  435 , a determination is made that the threshold time has been reached, then the flowchart continues at  440  and the window size is increased. That is, the number of frames used to detect a touch type is increased such that the touch type is determined over a longer period of time. 
     After the window is increased, or if at  435  a determination is made that the threshold time has not been met, then the flowchart continues at  445 , where the touch detection module  135  continues to process the touch data using the current filter in order to detect a touch. The flowchart then returns to  410  and the next plurality of frames of the current window size is received. As such, the number of frames that is used to detect a touch type remains constant such that the touch type continues to be determined periodically. 
     Referring now to  FIG. 5 , a simplified functional block diagram of illustrative multifunction electronic device  500  is shown according to one embodiment. Each of electronic device  100 , first wearable device  150  and second wearable device  175  may be a multifunctional electronic device, or may have some or all of the described components of a multifunctional electronic device described herein. Multifunction electronic device  500  may include processor  505 , display  510 , user interface  515 , graphics hardware  520 , device sensors  525  (e.g., proximity sensor/ambient light sensor, accelerometer and/or gyroscope), microphone  530 , audio codec(s)  535 , speaker(s)  540 , communications circuitry  545 , digital image capture circuitry  550  (e.g., including camera system) video codec(s)  555  (e.g., in support of digital image capture unit), memory  560 , storage device  565 , and communications bus  570 . Multifunction electronic device  500  may be, for example, a digital camera or a personal electronic device such as a personal digital assistant (PDA), personal music player, mobile telephone, or a tablet computer. 
     Processor  505  may execute instructions necessary to carry out or control the operation of many functions performed by device  500  (e.g., such as the generation and/or processing of images as disclosed herein). Processor  505  may, for instance, drive display  510  and receive user input from user interface  515 . User interface  515  may allow a user to interact with device  500 . For example, user interface  515  can take a variety of forms, such as a button, keypad, dial, a click wheel, keyboard, display screen and/or a touch screen. Processor  505  may also, for example, be a system-on-chip such as those found in mobile devices and include a dedicated graphics processing unit (GPU). Processor  505  may be based on reduced instruction-set computer (RISC) or complex instruction-set computer (CISC) architectures or any other suitable architecture and may include one or more processing cores. Graphics hardware  520  may be special purpose computational hardware for processing graphics and/or assisting processor  505  to process graphics information. In one embodiment, graphics hardware  520  may include a programmable GPU. 
     Image capture circuitry  550  may include two (or more) lens assemblies  580 A and  580 B, where each lens assembly may have a separate focal length. For example, lens assembly  580 A may have a short focal length relative to the focal length of lens assembly  580 B. Each lens assembly may have a separate associated sensor element  590 . Alternatively, two or more lens assemblies may share a common sensor element. Image capture circuitry  550  may capture still and/or video images. Output from image capture circuitry  550  may be processed, at least in part, by video codec(s)  555  and/or processor  505  and/or graphics hardware  520 , and/or a dedicated image processing unit or pipeline incorporated within circuitry  565 . Images so captured may be stored in memory  560  and/or storage  565 . 
     Sensor and camera circuitry  550  may capture still and video images that may be processed in accordance with this disclosure, at least in part, by video codec(s)  555  and/or processor  505  and/or graphics hardware  520 , and/or a dedicated image processing unit incorporated within circuitry  550 . Images so captured may be stored in memory  560  and/or storage  565 . Memory  560  may include one or more different types of media used by processor  505  and graphics hardware  520  to perform device functions. For example, memory  560  may include memory cache, read-only memory (ROM), and/or random access memory (RAM). Storage  565  may store media (e.g., audio, image and video files), computer program instructions or software, preference information, device profile information, and any other suitable data. Storage  565  may include one more non-transitory computer-readable storage mediums including, for example, magnetic disks (fixed, floppy, and removable) and tape, optical media such as CD-ROMs and digital video disks (DVDs), and semiconductor memory devices such as Electrically Programmable Read-Only Memory (EPROM), and Electrically Erasable Programmable Read-Only Memory (EEPROM). Memory  560  and storage  565  may be used to tangibly retain computer program instructions or code organized into one or more modules and written in any desired computer programming language. When executed by, for example, processor  505  such computer program code may implement one or more of the methods described herein. 
     The scope of the disclosed subject matter should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.”

Metadata:
Filing Date: 20200617
Publication Date: 20220201
Grant Date: 20220201
Priority Date: 20190617
Inventors: WANG, Lejing
BEN HIMANE, MOHAMED SELIM
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F3/0425", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/04186", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04186", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0421", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/04186", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 80034678