# US 2023/0068614 A1 · Method and device for aligning color channels > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2023/0068614 A1 - Document ID: US20230068614A1 - Status: Published application - Kind: A1 - Application number: 17/411,717 - Filed: 2021-08-25 - Published: 2023-03-02 - Earliest claimed: 2021-08-25 - Assignees: Christie Digital Systems USA, Inc. - Applicants: Christie Digital Systems USA, Inc. - Inventors: Andrew Dennison; Christopher John Gordon; Simon Thomson; Peter Anthony Van Eerd; Colin Bartlett Yardley; Chad Faragher - Web page: https://patentgrep.com/patent/US20230068614A1 ## CPC - 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 9/3155: {for controlling the light source (light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406)} - H04N 9/3182: {Colour adjustment, e.g. white balance, shading or gamut (white balance per se H04N9/73; control of amplitude of colour signals H04N9/68; colour control circuits for displays in general G09G5/02, G09G3/2003, G09G3/3607)} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method of aligning a plurality of color channels of a projector is provided. The method includes: for each color channel, (i) projecting test pattern on a surface; (ii) capturing image of the test pattern generated on the surface; and (iii) adding the captured image to an image set. Once the captured images for each color channel are added to an image set, identifying a reference position based on the image set. This is followed by processing the image set to estimate a divergence of the respective test patterns for each color channel with respect to the reference position, followed by computing a corrective function for each color channel and applying the respective corrective function to each color channel to align the color channel to the reference position. ## Claims ### Claim 1 A method of aligning a plurality of color channels of a projector comprising: for each color channel: (i) projecting a test pattern on a surface; (ii) capturing an image of the test pattern generated on the surface; (iii) adding the captured image to an image set; identifying a reference position based on the image set; processing the image set, comprising the images for all of the color channels, to estimate a divergence of the respective test patterns for each color channel with respect to the reference position; computing a corrective function for each color channel based on the estimated divergence from the reference position; applying the respective corrective function to a respective one of a plurality of microdisplay devices corresponding to each color channel to align the color channel to the reference position. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein projecting the test pattern on the surface comprises projecting test patterns for at least two color channels simultaneously and wherein the image set comprises at least one single image of the test patterns simultaneously projected by the at least two color channels. ### Claim 3 (canceled) ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein applying the corrective function to the respective microdisplay devices comprises electronically controlling the microdisplay device to warp the color channel according to the corrective function. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein applying the corrective function to the respective microdisplay devices comprises electronically controlling at least one motor coupled to the respective microdisplay devices to align a position of the respective microdisplay devices according to the corrective function. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein identifying the reference position comprises selecting the reference position from the plurality of color channels of the projector. ### Claim 7 (depends on 1) The method as claimed in claim 1, wherein identifying the reference position comprises defining the reference position as an average of respective projection positions of the color channels. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein identifying the reference position comprises defining the reference position as an intersection of respective projection positions of the color channels. ### Claim 9 (depends on 1) The method as claimed in claim 1, further comprising pairing the projector with one or more external projectors and applying an external corrective function based on a white level projection difference of the projector with respect to the one or more external projectors. ### Claim 10 A projector comprising: a plurality of microdisplay devices configured to project a corresponding plurality of color channels; a camera configured to capture images of the projected color channels; a processor configured to: control the microdisplay devices to project a plurality of test patterns on a surface for at least two color channels; add the captured images of the projected color channels to an image set; identify a reference position based on the image set; process the image set to estimate divergence of the respective test patterns for each color channel with respect to the reference position; compute a corrective function for each color channel based on the estimated divergence from the reference position; apply the respective corrective function to each microdisplay device to align the respective color channel to the reference position. ### Claim 11 (canceled) ### Claim 12 (depends on 10) The projector as claimed in claim 10, wherein the processor is configured to control the respective microdisplay devices to warp the color channels according to the corrective function. ### Claim 13 (depends on 10) The projector as claimed in claim 10, further comprising at least one motor coupled to the respective microdisplay devices wherein the processor controls the motor to align the respective microdisplay devices according to the corrective function. ### Claim 14 (depends on 10) The projector as claimed in claim 10, wherein the processor is configured to save the respective corrective functions of color channels. ### Claim 15 A system comprising: a projector comprising a plurality of microdisplay devices configured to project a corresponding plurality of color channels; a camera configured to capture images of the projected color channels; a processor configured to: control the microdisplay devices to project a plurality of test patterns on a surface for at least two color channels; add the captured images of the projected color channels to an image set; identify a reference position based on the image set; process the image set to estimate divergence of the respective test patterns for each color channel with respect to the reference position; compute a corrective function for each color channel based on the estimated divergence from the reference position; apply the respective corrective function to a respective one of the microdisplay devices corresponding to each color channel to align the color channel to the reference position.