# US 10,321,106 B2 · Position detection apparatus and contrast adjustment method used with the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,321,106 B2 - Document ID: US10321106B2 - Status: Granted - Kind: B2 - Application number: 15/425,792 - Filed: 2017-02-06 - Published: 2017-08-17 - Granted: 2019-06-11 - Earliest claimed: 2016-02-17 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Takaaki Koyama - Web page: https://patentgrep.com/patent/US10321106B2 ## CPC - G06F 3/0416: {Control or interface arrangements specially adapted for digitisers} - G06F 3/00: Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements - G06F 3/0418: {for error correction or compensation, e.g. based on parallax, calibration or alignment} - G06F 3/0421: {by interrupting or reflecting a light beam, e.g. optical touch-screen} - G06T 7/70: Determining position or orientation of objects or cameras (camera calibration G06T7/80) - H04N 9/3188: {Scale or resolution adjustment (scaling in general G06T3/40; resolution modifying circuits for displays in general G09G5/391)} - H04N 9/3194: {including sensor feedback} - G06F 2203/04104: Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger - G06T 2207/10016: Video; Image sequence - G06T 2207/10152: Varying illumination - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A position detection apparatus includes a first irradiation section and a second irradiation section that irradiate an operation surface with detection light, an imaging section that captures an image of the operation surface, and a detection section that detects a pointed position pointed with a pointing element based on the captured image. The first irradiation section is disposed in a position closer to the operation surface than the second irradiation section and emits light having intensity higher than the intensity of the light emitted from the second irradiation section. Instead, the position detection apparatus further includes an adjustment section that adjusts the intensity of the light emitted from at least one of the first irradiation section and the second irradiation section to adjust contrast between the pointing element and the operation surface to a value that exceeds a threshold. ## Claims ### Claim 1 A position detection apparatus that detects a pointed position pointed with a pointing element on an operation surface, the apparatus comprising: a first irradiation section and a second irradiation section that irradiate the operation surface with detection light; an imaging section that captures an image of the operation surface; and at least one processor configured to detect the pointed position pointed with the pointing element based on a contrast between the pointing element and the projected screen in the captured image captured by the imaging section, wherein the first irradiation section is disposed in a position closer to the operation surface than the second irradiation section and emits light having intensity higher than intensity of the light emitted from the second irradiation section, the first irradiation section and the second irradiation section emit the detection light in a time division manner, and the imaging section performs the imaging in each of a period for which the first irradiation section emits light and a period for which the second irradiation section emits light. ### Claim 2 A position detection apparatus that detects a pointed position pointed with a pointing element on an operation surface, the apparatus comprising: a first irradiation section and a second irradiation section that irradiate the operation surface with detection light; an imaging section that captures an image of the operation surface; and at least one processor configured to: detect the pointed position pointed with the pointing element based on the captured image captured by the imaging section; acquire a use environment in which the position detection apparatus is used, and adjust the intensity of the light emitted from at least one of the first irradiation section and the second irradiation section, in accordance with the use environment in which the position detection apparatus is used, to adjust contrast between the pointing element and the operation surface in the captured image to a value that exceeds a threshold, wherein the use environment includes at least one of posture of the installed position detection apparatus, a distance between the position detection apparatus and the operation surface, and brightness of the operation surface under environmental light. ### Claim 3 (depends on 2) The position detection apparatus according to claim 2, wherein the first irradiation section is disposed in a position closer to the operation surface than the second irradiation section, and the at least one processor is further configured to adjust the intensity of the light emitted from the first irradiation section to a value higher than the intensity of the light emitted from the second irradiation section. ### Claim 4 (depends on 1) The position detection apparatus according to claim 1, wherein the intensity of the light emitted from each of the first irradiation section and the second irradiation section is so adjusted that a sum of a first area where first contrast obtained when the first irradiation section emits light exceeds a threshold and a second area where second contrast obtained when the second irradiation section emits light exceeds another threshold encompasses an entire area of the operation surface. ### Claim 5 (depends on 1) The position detection apparatus according to claim 1, further comprising a projection section that projects an image on the operation surface. ### Claim 6 A contrast adjustment method used with a position detection apparatus that detects a pointed position pointed with a pointing element on an operation surface, the method comprising: (a) irradiating the operation surface with detection light by using a first irradiation section and a second irradiation section; (b) capturing an image of the operation surface; (c) detecting the pointed position pointed with the pointing element based on the captured image captured in the step (b); (d) acquiring a use environment in which the position detection apparatus is used, and (e) adjusting intensity of the light emitted from at least one of the first irradiation section and the second irradiation section, in accordance with the use environment in which the position detection apparatus is used, to adjust contrast between the pointing element and the operation surface in the captured image to a value that exceeds a threshold, wherein the use environment includes at least one of posture of the installed position detection apparatus, a distance between the position detection apparatus and the operation surface, and brightness of the operation surface under environmental light. ### Claim 7 (depends on 1) The position detection apparatus according to claim 1, wherein the first irradiation section is disposed in a position closer to the operation surface than the first imaging section, and the second irradiation section is disposed in a position farther from the operation surface than the first imaging section. ### Claim 8 (depends on 1) The position detection apparatus according to claim 1, further comprising: a second imaging section that captures an image of the operation surface from a position different from the first imaging section, wherein the second imaging section is disposed in a position closer to the operation surface than the first imaging section and the second irradiation section. ### Claim 9 (depends on 5) The position detection apparatus according to claim 5, wherein the first irradiation section is disposed in a position closer to the operation surface than the projection section, and the second irradiation section is disposed in a position farther from the operation surface than the projection section. ### Claim 10 A position detection apparatus that detects a pointed position pointed with a pointing element on an operation surface, the apparatus comprising: a first irradiation section and a second irradiation section that irradiate the operation surface with detection light; an imaging section that captures an image of the operation surface; and at least one processor configured to detect the pointed position pointed with the pointing element based on a contrast between the pointing element and the projected screen in the captured image captured by the imaging section, wherein the first irradiation section is disposed in a position closer to the operation surface than the second irradiation section and emits light having intensity higher than intensity of the light emitted from the second irradiation section, and the intensity of the light emitted from each of the first irradiation section and the second irradiation section is so adjusted that a sum of a first area where first contrast obtained when the first irradiation section emits light exceeds a threshold and a second area where second contrast obtained when the second irradiation section emits light exceeds another threshold encompasses an entire area of the operation surface.