# US 10,321,110 B2 · Method and apparatus for image processing > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,321,110 B2 - Document ID: US10321110B2 - Status: Granted - Kind: B2 - Application number: 15/313,224 - Filed: 2014-05-29 - Published: 2017-07-06 - Granted: 2019-06-11 - Earliest claimed: 2014-05-29 - Assignees: Nokia Technologies Oy - Applicants: Nokia Technologies Oy - Inventors: Zhuo Jiang; Xiaopeng Lu; Wei Zong; Lingnan Li - Web page: https://patentgrep.com/patent/US10321110B2 ## CPC - H04N 23/88: for colour balance, e.g. white-balance circuits or colour temperature control - G06T 7/90: Determination of colour characteristics - G06T 2207/10024: Color image - G06T 2207/20021: Dividing image into blocks, subimages or windows - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A method, corresponding apparatuses, and a non-transitory computer readable medium for image processing are provided. A method comprises selecting at least one reference point on a sensor illumination response curve in a sensor illumination response plane. The method further comprises determining at least one dominant color evaluation region in the sensor illumination response plane based on the at least one reference point. With the claimed inventions, color reproduction performance could be improved. ## Claims ### Claim 1 A method, comprising: selecting at least one reference point on a sensor illumination response curve in a sensor illumination response plane; determining at least one dominant color evaluation region in the sensor illumination response plane based on the at least one reference point; dividing an image into a plurality of grids; evaluating whether at least some of the grids of the plurality of grids are associated with the at least one dominant color evaluation region based on a sensor red color response per sensor green color response, and a sensor blue color response per sensor green color response of each grid; determining that the image comprises the at least one dominant color if a number of grids that are associated with the at least one dominant color evaluation region satisfies a threshold; and adjusting, subsequent to determining that the image contains the at least one dominant color, the at least one dominant color in a UV color domain by fine tune parameters. ### Claim 2 (depends on 1) The method according to claim 1, wherein the sensor illumination response curve is formed based on red color, blue color and green color components of a testing image, and the selecting the at least one reference point comprises selecting, as the at least one reference point, a point where a sensor red color response per sensor green color response and a sensor blue color response per sensor green color response of the testing image to an illumination are the same on the sensor illumination response curve. ### Claim 3 (depends on 1) The method according to claim 1, further comprising disabling a grey world balance algorithm for a grid that is associated with the at least one dominant color evaluation region. ### Claim 4 (depends on 1) The method according to claim 1, further comprising disabling a contrast enhancement to the image if the image has been determined as a single dominant color image. ### Claim 5 An apparatus, comprising: at least one processor; and at least one memory comprising computer program instructions, wherein the at least one memory and the computer program instructions are configured to, with the at least one processor, cause the apparatus at least to: select at least one reference point on a sensor illumination response curve in a sensor illumination response plane; determine at least one dominant color evaluation region in the sensor illumination response plane based on the at least one reference point; divide an image into a plurality of grids; evaluate whether at least some of the grids of the plurality of grids are associated with the at least one dominant color evaluation region based on a sensor red color response per sensor green color response, and a sensor blue color response per sensor green color response of each grid; determine that the image comprises the at least one dominant color if a number of grids that are associated with the at least one dominant color evaluation region satisfies a threshold; and adjust, subsequent to determining that the image contains the at least one dominant color, the at least one dominant color in a UV color domain by fine tune parameters. ### Claim 6 (depends on 5) The apparatus according to claim 5, wherein the sensor illumination response curve is formed based on red color, blue color and green color components of a testing image, and the at least one memory and computer program instructions are configured to, with the at least one processor, cause the apparatus further to: select, as the at least one reference point, a point where a sensor red color response per sensor green color response and a sensor blue color response per sensor green color response of the testing image to an illumination are the same on the sensor illumination response curve. ### Claim 7 (depends on 5) The apparatus according to claim 5, wherein the at least one memory and computer program instructions are configured to, with the at least one processor, cause the apparatus further to: disable a grey world balance algorithm for a grid that is associated with the at least one dominant color evaluation region. ### Claim 8 (depends on 5) The apparatus according to claim 5, wherein the at least one memory and computer program instructions are configured to, with the at least one processor, cause the apparatus further to: disable a contrast enhancement to the image if the image has been determined as a single dominant color image. ### Claim 9 A non-transitory computer readable medium having program code stored thereon, the program code configured to direct an apparatus, when executed, to: select at least one reference point on a sensor illumination response curve in a sensor illumination response plane; determine at least one dominant color evaluation region in the sensor illumination response plane based on the at least one reference point; divide an image into a plurality of grids; evaluate whether at least some of the grids of the plurality of grids are associated with the at least one dominant color evaluation region based on a sensor red color response per sensor green color response, and a sensor blue color response per sensor green color response of each grid; determine that the image comprises the at least one dominant color if a number of grids that are associated with the at least one dominant color evaluation region satisfies a threshold; and adjust, subsequent to determining that the image contains the at least one dominant color, the at least one dominant color in a UV color domain by fine tune parameters. ### Claim 10 (depends on 9) The non-transitory computer readable medium according to claim 9, wherein the sensor illumination response curve is formed based on red color, blue color and green color components of a testing image, and the program code is configured to further direct the apparatus, when executed, to: select, as the at least one reference point, a point where a sensor red color response per sensor green color response and a sensor blue color response per sensor green color response of the testing image to an illumination are the same on the sensor illumination response curve. ### Claim 11 (depends on 9) The non-transitory computer readable medium according to claim 9, wherein the program code is configured to further direct the apparatus, when executed, to disable a grey world balance algorithm for a grid that is associated with the at least one dominant color evaluation region. ### Claim 12 (depends on 9) The non-transitory computer readable medium according to claim 9, wherein the program code is configured to further direct the apparatus, when executed, to disable a contrast enhancement to the image if the image has been determined as a single dominant color image.