# US 2017/0285873 A1 · Coherent illumination for touch point identification > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0285873 A1 - Document ID: US20170285873A1 - Status: Published application - Kind: A1 - Application number: 15/508,385 - Filed: 2014-09-05 - Published: 2017-10-05 - Earliest claimed: 2014-09-05 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: Hewlett-Packard Development Company, L.P. - Inventors: Kar-Han Tan; David Bradley Short; Jinman Kang - Web page: https://patentgrep.com/patent/US20170285873A1 ## CPC - G06F 3/0421: {by interrupting or reflecting a light beam, e.g. optical touch-screen} - G06F 3/0425: {using a single imaging device like a video camera for tracking the absolute position of a single or a plurality of objects with respect to an imaged reference surface, e.g. video camera imaging a display or a projection screen, a table or a wall surface, on which a computer generated image is displayed or projected (tracking a projected light spot to determine a position on a display surface G06F3/0386)} - G06F 18/22: Matching criteria, e.g. proximity measures - G06T 7/20: Analysis of motion (motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51) - G06T 7/248: {involving reference images or patches} - G06V 10/145: Illumination specially adapted for pattern recognition, e.g. using gratings - G06V 40/28: {Recognition of hand or arm movements, e.g. recognition of deaf sign language (static hand signs G06V40/113)} - G06T 2207/10141: Special mode during image acquisition - G06T 2207/30196: Human being; Person - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING ## Abstract A system includes a sensor to capture multiple images of a portion of a first object illuminated by coherent illumination and a time of capture of each of the images; and a processor to compare two images of the multiple images to identify one or more touch points. Each touch point has a difference in value between the two images that is greater than a threshold. Upon determining a spatial shape formed by the identified touch points that corresponds to a pointing end of a pointing object, the system provides at least one of: i) a touch location of the pointing end relative to the first object, where the touch location is based on the spatial shape formed by the identified touch points, or ii) the time of capture of a second image of the two images that produced the spatial shape. ## Claims ### Claim 1 A system comprising: a first sensor to capture a plurality of first images of a portion of a first object illuminated by coherent illumination and a time of capture of each of the plurality of first images; and a processor to: compare two images of the plurality of first images to identify one or more touch points, wherein each touch point has a difference in value between the two images that is greater than a threshold; and upon determining a spatial shape formed by the identified touch points that corresponds to a pointing end of a pointing object, providing at least one of: i) a touch location of the pointing end relative to the first object, wherein the touch location is based on the spatial shape formed by the identified touch points or ii) the time of capture of the two images that produced the spatial shape. ### Claim 2 (depends on 1) The system of claim 1, wherein the processor is further to: from the plurality of first images, track one or more pointing ends of the pointing object, wherein comparing the two images comprises comparing regions near the one or more pointing ends of the two images. ### Claim 3 (depends on 1) The system of claim 1, further comprising: a tracking sensor to capture a plurality of tracking images of the portion of the first object, wherein the processor is further to: from the plurality of tracking images, track or identify one or more pointing ends of the pointing object, wherein comparing the two images comprises comparing regions near the one or more pointing ends of the two images. ### Claim 4 (depends on 1) The system of claim 1, wherein the processor is further to: from the plurality of first images, identify touch points having a spatial shape corresponding to one or more pointing ends of the pointing object, wherein comparing the two images comprises comparing regions near the spatial shape of the two images. ### Claim 5 (depends on 4) The system of claim 4, wherein the processor is further to: associate the spatial shape with a first pressure of the pointing object against the first object; upon determining a change in size of the spatial shape in subsequent images of the plurality of first images, associating a second pressure of the pointing object against the first object, wherein the second pressure is based on the change in size of the spatial shape; and providing as an output the first pressure and the second pressure. ### Claim 6 (depends on 1) The system of claim 1, further comprising: a scanning mechanism to scan light from a light source generating the coherent illumination over the portion of the first object to illuminate the portion of the first object while capturing the plurality of first images. ### Claim 7 (depends on 1) The system of claim 1, further comprising: optics to spread light from a light source generating the coherent illumination over the portion of the first object while capturing the plurality of first images. ### Claim 8 A method comprising: receiving a series of first images that includes a monitored object illuminated by a coherent light source, wherein each of the first images includes a time of capture; comparing values of corresponding pixels of two images of the series of first images to identify touch pixels, wherein each touch pixel changes in value between the two images, and the change is greater than a threshold; and upon identifying a spatial pattern of touch pixels that corresponds to a pointing end of a pointing object, providing at least one of: i) a touch location of the pointing end relative to the monitored object, wherein the touch location is based on the spatial pattern of touch pixels, or the time of capture of the two images that produced the spatial pattern. ### Claim 9 (depends on 8) The method of claim 8, further comprising: tracking one or more pointing ends of the pointing object from the series of first images, wherein comparing corresponding pixels comprises comparing corresponding pixels in a region around the identified one or more pointing ends. ### Claim 10 (depends on 8) The method of claim 8, further comprising: receiving a series of second images; and tracking one or more pointing ends of the pointing object from the series of second images, wherein comparing corresponding pixels comprises comparing corresponding pixels in a region around the identified one or more pointing ends. ### Claim 11 (depends on 8) The method of claim 8, further comprising: illuminating the monitored object by scanning light the coherent light source over the monitored object. ### Claim 12 (depends on 8) The method of claim 8, further comprising: spreading light from the coherent light source to illuminate the monitored object a the field of view of a sensor while capturing the series of first images with the sensor. ### Claim 13 A non-transitory computer readable medium storing instructions causing a processor to: compare pixels of a first pair of images of a series of images of an item illuminated by coherent illumination to identify touch pixels, wherein a difference in value of each touch pixel between the two images is greater than a threshold; identify and store a first pattern of touch pixels that corresponds to a pointing end of a pointing object; compare pixels of a second pair of images of the series of images; identify and store a second pattern of touch pixels that corresponds to the pointing end of the pointing object. ### Claim 14 (depends on 13) The non-transitory computer readable medium claim 13, wherein stored instructions further cause the processor to: associate the first pattern with a first pressure of the pointing object against the item; upon determining a change in size of the second pattern from the first pattern, associate the second pattern with a second pressure of the pointing object against the item, wherein the second pressure is based on the change in size; and providing i) the first pressure and the second pressure, or ii) a qualitative difference between the first pressure and the second pressure. ### Claim 15 (depends on 1) The non-transitory computer readable medium of claim 1 wherein the stored instructions further cause the processor to: associate the first pattern with a touch of the pointing object against the item; upon determining a change in size of the second pattern in subsequent images of the series of images from the first pattern, wherein the change is greater than a given change, associate the second pattern with a change in pressure of the pointing object against the item, and provide a notification that a change in pressure has occurred.