# US 8,542,267 B1 · Calibrating a visual-collaborative system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,542,267 B1 - Document ID: US8542267B1 - Status: Granted - Kind: B1 - Application number: 12/571,529 - Filed: 2009-10-01 - Granted: 2013-09-24 - Earliest claimed: 2009-10-01 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: Mitchell Trott; Kar-Han Tan - Inventors: Mitchell Trott; Kar-Han Tan - Web page: https://patentgrep.com/patent/US8542267B1 ## CPC - H04N 17/002: {for television cameras} - G03B 17/54: with projector - G06F 3/011: {Arrangements for interaction with the human body, e.g. for user immersion in virtual reality (blind teaching G09B21/00)} - 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)} - H04N 9/3185: {Geometric adjustment, e.g. keystone or convergence (optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14)} - H04N 9/3194: {including sensor feedback} - H04N 23/62: Control of parameters via user interfaces - H04N 7/15: Conference systems - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A calibration system including a display screen having a first surface and a second surface and a projector configured to project an image onto the first surface of the display screen and the image is viewable on the second surface of said display screen, wherein the projector includes a projector coordinate system. The calibration system also includes a camera configured to capture an image of an object through the display screen, where the camera comprises a camera coordinate system, and a calibration device configured to calibrate the display screen. ## Claims ### Claim 1 A calibration system comprising: a display screen comprising a first surface and a second surface; a projector configured to project an image onto said first surface of the display screen and said image is viewable on said second surface of said display screen, wherein said projector comprises a projector coordinate system; a camera configured to capture an image of an object through said display screen, wherein said camera comprises a camera coordinate system; and a calibration device configured to calibrate said display screen. ### Claim 2 (depends on 1) The system of claim 1, wherein said calibration device comprises: a light source configured to emit light towards said camera, wherein said light source is disposed at a known coordinate proximate and relative to said display screen. ### Claim 3 (depends on 1) The system of claim 1, wherein said calibration device comprises: a light sensor configured to receive projector calibration images from said projector, wherein said light sensor is disposed at a known coordinate proximate and relative to said display screen. ### Claim 4 (depends on 3) The system of claim 3, wherein said projector calibration images comprise: binary light patterns associated with a plurality of pixels in a field of coverage of said projector. ### Claim 5 (depends on 1) The system of claim 1, comprising: a touch sensing system configured to sense a location of a touch pressure on said display screen, wherein said touch sensing system comprises a touch coordinate system and wherein said projector coordinate system, said camera coordinate system and said touch coordinate system are calibrated based at least on said location of said touch pressure on said second surface of said display screen. ### Claim 6 (depends on 1) The system of claim 1, wherein said calibration device is disposed proximate to said display screen. ### Claim 7 A method for calibration, said method comprising: receiving a projector calibration image from a projector at a projector calibration device, wherein said prosector is configured to project an image onto a first surface of a display screen and said image is viewable on a second surface of said display screen; emitting light from a camera calibration device towards a camera, wherein said camera is configured to capture an image through said display screen; and calibrating said display screen based at least on said received projector calibration image and said emitted light. ### Claim 8 (depends on 7) The method of claim 7, wherein said projector calibration device, comprises: a light sensor disposed proximate to said display screen and at a known coordinate relative to said display screen. ### Claim 9 (depends on 7) The method of claim 7, wherein said camera calibration device, comprises: a light source disposed proximate to said display screen and at a known coordinate relative to said display screen. ### Claim 10 (depends on 9) The method of claim 9, wherein said projection calibration image comprises: binary light patterns associated with each pixel in a field of coverage of said projector. ### Claim 11 (depends on 7) The method of claim 7, comprising: receiving a touch signal at a touch sensing system, wherein said projector coordinate system, said camera coordinate system and a touch sensing system coordinate system are calibrated based at least on said received touch signal by said touch sensing system. ### Claim 12 (depends on 7) The method of claim 7, wherein said projector calibration device and said camera calibration device combined, comprise: a light receiver/emitter device configured to receive said projector calibration image in a first frequency and emit light in a second frequency towards said camera, wherein said light receiver/emitter is disposed at a known coordinate proximate and relative to said display screen. ### Claim 13 A calibration system comprising: a projector configured to project an image onto a first surface of a display screen and a calibration surface, wherein said projector comprises a projector coordinate system, and wherein said image projected onto said first surface of said display screen is viewable on a second surface of said display screen; and a camera configured to capture said image through said display screen and on said calibration surface such that a camera coordinate system and said projector coordinate system are calibrated. ### Claim 14 (depends on 13) The system of claim 13, wherein said calibration surface is disposed on a perimeter of said display surface. ### Claim 15 (depends on 13) The system of claim 13, comprising: a housing, wherein said projector, said camera and said calibration surface are disposed in said housing. ### Claim 16 (depends on 13) The system of claim 13, comprising: a filter configured to block said image projected on said display screen from said camera. ### Claim 17 (depends on 13) The system of claim 13, comprising: a filter configured to pass light received by said camera and substantially block said image produced by said projector. ### Claim 18 (depends on 17) The system of claim 17, wherein said filter is temporarily disabled such that said camera coordinate system and said projector coordinate system are calibrated. ### Claim 19 (depends on 17) The system of claim 17, wherein said filter comprises: an electrically adjustable filter such that said image produced by said projector is captured by said camera such that said camera coordinate system and said projector coordinate system are calibrated.