# US 2017/0257607 A1 · Non-uniformity output determination for light projectors > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0257607 A1 - Document ID: US20170257607A1 - Status: Published application - Kind: A1 - Application number: 15/446,250 - Filed: 2017-03-01 - Published: 2017-09-07 - Earliest claimed: 2016-03-01 - Assignees: University of Delaware - Inventors: Fouad Kiamilev; Andrea Waite - Web page: https://patentgrep.com/patent/US20170257607A1 ## CPC - 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 9/3138: {using arrays of modulated light sources (electroluminescent display devices G09G3/30)} - H04N 9/3164: {using multiple light sources} - 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 9/3191: {Testing thereof (testing of displays in general G09G3/006)} - H04N 9/3194: {including sensor feedback} - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract The present invention relates to a calibration system and method including a pixelated display including pixels for projecting an image, an imager positioned to capture the image produced by the pixelated display, and a processor. The processor is configured to determine and measure non-uniformity in the image produced by the pixelated display by repeatedly selecting and illuminating a subset of the pixels in the pixelated display with respective driving currents, controlling the imager to capture the image projected by the subset pixels, determining and storing, for each pixel in the subset, an intensity value produced in response to the respective driving current, and updating, for each pixel in the subset, the respective driving currents based on the determined intensity value and previously stored intensity values corresponding with previously stored driving currents. ## Claims ### Claim 1 A calibration system comprising: a pixelated display including pixels for projecting an image; an imager positioned to capture the image produced by the pixelated display; and a non-uniformity determination processor configured to perform measurement of non-uniformity in the image produced by the pixelated display by repeatedly: a) selecting and illuminating a subset of the pixels in the pixelated display with respective driving currents, b) controlling the imager to capture the image projected by the subset pixels, c) determining and storing, for each pixel in the subset, an intensity value produced in response to the respective driving current, and d) updating, for each pixel in the subset, the respective driving currents based on the determined intensity value and previously stored intensity values corresponding with previously stored driving currents. ### Claim 2 (depends on 1) The calibration system of claim 1, wherein, to update the respective driving currents, the non-uniformity determination processor is further configured to: determine, for each pixel in the subset, a first slope computed between the determined intensity value and at least a first previously stored intensity value at a corresponding first driving current, determine, for each pixel in the subset, a second slope computed between the determined intensity value and at least a second previously stored intensity value at a corresponding second driving current, choose, for each pixel in the subset, the greatest of the first slope, the second slope, or any other slope previously computed for that respective pixel, and update, for each pixel in the subset, the respective driving current to a value that corresponds to an intensity value along the chosen slope. ### Claim 3 (depends on 1) The calibration system of claim 1, wherein the non-uniformity determination processor is further configured to: illuminate a different subset of the pixels in the pixelated display with respective driving currents after a number of iterations of steps (a)-(d) are complete, and repeatedly perform steps (a)-(d) on the different subset of the pixels. ### Claim 4 (depends on 1) The calibration system of claim 1, wherein the non-uniformity determination processor is further configured to: select positions of the subset of the pixels within the pixelated display such that cross-talk between the illuminated pixels in the subset is below a threshold when performing perform steps (a)-(d). ### Claim 5 (depends on 1) The calibration system of claim 1, wherein the pixelated display includes a grid of infrared (IR) light emitting diodes (LEDs) as the pixels. ### Claim 6 (depends on 1) The calibration system of claim 1, wherein the non-uniformity determination processor is further configured to: stop performing steps (a)-(d) on the selected subset of the pixels when a threshold is reached, the threshold being a threshold number of iterations, a threshold difference in intensity between iterations, or a threshold difference in driving current between iterations. ### Claim 7 (depends on 1) The calibration system of claim 1, wherein after the subset of the pixels are corrected, the non-uniformity determination processor is further configured to: send the stored pixel intensity values and corresponding driving currents for each pixel in the subset to the pixelated display, such that images projected by the pixelated display are corrected. ### Claim 8 (depends on 2) The calibration system of claim 2, wherein the non-uniformity determination processor is further configured to: update, for each pixel in the subset, the respective driving current value, by selecting a driving current located midway between respective driving currents corresponding to the intensity values defining the slope. ### Claim 9 (depends on 1) The calibration system of claim 1, wherein, after the pixels in the subset are corrected, the non-uniformity determination processor is further configured to: perform curve fitting for the stored data of each pixel to derive a curve, and drive the pixelated display using the derived curve, such that images projected by the pixelated display are corrected. ### Claim 10 (depends on 1) The calibration system of claim 1, wherein the non-uniformity determination processor is further configured to: perform steps (a)-(d) in between video frames while a video is being projected by the pixelated display. ### Claim 11 A non-uniformity determination method for a pixelated display including pixels for projecting an image, the method comprising: capturing, by an imager, the image produced by the pixelated display; and performing, by a non-uniformity determination processor, determination of non-uniformity in the image produced by the pixelated display by repeatedly: a) selecting and illuminating a subset of the pixels in the pixelated display with respective driving currents, b) controlling the imager to capture the image projected by the subset pixels, c) determining and storing, for each pixel in the subset, an intensity value produced in response to the respective driving current, and d) updating, for each pixel in the subset, the respective driving currents based on the determined intensity value and previously stored intensity values corresponding with previously stored driving currents. ### Claim 12 (depends on 11) The non-uniformity determination method of claim 11, further comprising: updating, by the non-uniformity determination processor, the respective driving currents by: determining, for each pixel in the subset, a first slope computed between the determined intensity value and at least a first previously stored intensity value at a corresponding first driving current, determining, for each pixel in the subset, a second slope computed between the determined intensity value and at least a second previously stored intensity value at a corresponding second driving current, choosing, for each pixel in the subset, the greatest of the first slope, the second slope, or any other slope previously computed for that respective pixel, and updating, for each pixel in the subset, the respective driving current to a value that corresponds to an intensity value along the chosen slope. ### Claim 13 (depends on 11) The non-uniformity determination method of claim 11, further comprising: illuminating, by the non-uniformity determination processor, a different subset of the pixels in the pixelated display with respective driving currents after a number of iterations of steps (a)-(d) are complete, and repeatedly performing, by the non-uniformity determination processor, steps (a)-(d) on the different subset of the pixels. ### Claim 14 (depends on 11) The non-uniformity determination method of claim 11, further comprising: selecting, by the non-uniformity determination processor, positions of the subset of the pixels within the pixelated display such that cross-talk between the illuminated pixels in the subset is below a threshold when performing perform steps (a)-(d). ### Claim 15 (depends on 11) The non-uniformity determination method of claim 11, wherein the pixelated display includes a grid of infrared (IR) light emitting diodes (LEDs) as the pixels. ### Claim 16 (depends on 11) The non-uniformity determination method of claim 11, further comprising: stopping performing steps (a)-(d) on the selected subset of the pixels, by the non-uniformity determination processor, when a threshold is reached, the threshold being a threshold number of iterations, a threshold difference in intensity between iterations, or a threshold difference in driving current between iterations. ### Claim 17 (depends on 11) The non-uniformity determination method of claim 11, further comprising: after the subset of the pixels are corrected, sending, by the non-uniformity determination processor, the stored pixel intensity values and corresponding driving currents for each pixel in the subset to the pixelated display, such that images projected by the pixelated display are corrected. ### Claim 18 (depends on 12) The non-uniformity determination method of claim 12, further comprising: updating, by the non-uniformity determination processor, for each pixel in the subset, the respective driving current value, by selecting a driving current located midway between respective driving currents corresponding to the intensity values defining the slope. ### Claim 19 (depends on 11) The non-uniformity determination method of claim 11, further comprising: after the pixels in the subset are corrected: performing, by the non-uniformity determination processor, curve fitting for the stored data of each pixel to derive a curve, and driving the pixelated display using the derived curve, such that images projected by the pixelated display are corrected. ### Claim 20 (depends on 11) The non-uniformity determination method of claim 11, further comprising: performing, by the non-uniformity determination processor, steps (a)-(d) in between video frames while a video is being projected by the pixelated display.