# US 10,504,217 B2 · Method and module for processing high dynamic range (HDR) image and display device using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,504,217 B2 - Document ID: US10504217B2 - Status: Granted - Kind: B2 - Application number: 15/700,847 - Filed: 2017-09-11 - Published: 2018-05-03 - Granted: 2019-12-10 - Earliest claimed: 2016-10-31 - Assignees: LG Display Co., Ltd. - Applicants: LG Display Co., Ltd. - Inventors: Yoo-Jin Kang; Sung-Jin Kim - Web page: https://patentgrep.com/patent/US10504217B2 ## CPC - G06T 5/92: based on global image properties - G06T 5/50: using two or more images, e.g. averaging or subtraction - G06T 7/136: involving thresholding - G09G 3/2092: {Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto (suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165)} - H04N 5/58: in dependence upon ambient light - H04N 23/63: by using electronic viewfinders - G06T 2207/20208: High dynamic range [HDR] image processing - G09G 5/005: {Adapting incoming signals to the display format of the display terminal} - G09G 5/006: {Details of the interface to the display terminal (specific for a display terminal using a CRT G09G1/167; using a flat panel G09G3/2096; circuits for interfacing with colour displays G09G5/04)} - G09G 2320/0271: Adjustment of the gradation levels within the range of the gradation scale, e.g. by redistribution or clipping - G09G 2320/06: Adjustment of display parameters - G09G 2320/062: Adjustment of illumination source parameters - G09G 2320/066: for control of contrast - G09G 2320/0666: for control of colour parameters, e.g. colour temperature - G09G 2320/0673: for control of gamma adjustment, e.g. selecting another gamma curve - G09G 2340/0428: Gradation resolution change - G09G 2360/144: the light being ambient light - G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract A method, display device and module for processing a high dynamic range (HDR) image are discussed. The method can include converting gray level information of a first HDR image into luminance information using a perceptual quantizer electro-optical transfer function (PQ-EOTF), and adjusting the luminance information according to illuminance information to obtain luminance information of a second HDR image; analyzing the luminance information of the second HDR image, and calculating a high-luminance rate of occupancy of pixels having a target peak luminance or more of a display device in the second HDR image; luminance-mapping the second HDR image to a third HDR image suitable for the display device using a mapping function changed according to the high-luminance rate; and converting luminance information of the third HDR image into gray level information of a fourth HDR image using a perceptual quantizer opto-electrical transfer function (PQ-OETF), and outputting the gray level information of the fourth HDR image. ## Claims ### Claim 1 An image processing method comprising: receiving illuminance information through an illuminance sensor; converting gray level information of a first high dynamic range (HDR) image into luminance information using a perceptual quantizer electro-optical transfer function (PQ-EOTF), and adjusting the luminance information according to the illuminance information to obtain luminance information of a second HDR image; analyzing the luminance information of the second HDR image, and calculating a high-luminance rate of occupancy of pixels having a target peak luminance or more of a display device in the second HDR image; luminance-mapping the second HDR image to a third HDR image suitable for the display device using a mapping function changed according to the high-luminance rate; and converting luminance information of the third HDR image into gray level information of a fourth HDR image using a perceptual quantizer opto-electrical transfer function (PQ-OETF), and outputting the gray level information of the fourth HDR image. ### Claim 2 (depends on 1) The method according to claim 1, wherein the second HDR image includes a first luminance part and a second luminance part, and wherein, in the luminance-mapping, when the high-luminance rate exceeds a threshold, a first linear mapping function is used in the first luminance part having the target peak luminance or less of the second HDR image and a second non-linear mapping function is used in the second luminance part having the target peak luminance or more, and when the high-luminance rate is equal to or less than the threshold, the first mapping function is used. ### Claim 3 (depends on 2) The method according to claim 2, wherein: when the high-luminance rate exceeds the threshold, luminance of the second luminance part of the second HDR image increases according to the second mapping function in a range between the target peak luminance of the display device and a maximum luminance of the display device, and when the high-luminance rate is equal to or less than the threshold, the second luminance part of the second HDR image is mapped to the target peak luminance. ### Claim 4 (depends on 1) The method according to claim 1, wherein the adjusting the luminance information according to the illuminance information includes: selecting a weight according to the illuminance information; and applying the weight to the luminance information to obtain the luminance information of the second HDR image. ### Claim 5 (depends on 4) The method according to claim 4, further comprising: storing weight information in association with illuminances in a look-up table which is to be used when selecting the weight. ### Claim 6 (depends on 1) The method according to claim 1, wherein the display device is a liquid crystal display (LCD) device or an organic light emitting diode (OLED) display device. ### Claim 7 An image processor comprising: an electro-optical transfer function (EOTF) sub-processor configured to receive illuminance information through an illuminance sensor, convert gray level information of a first high dynamic range (HDR) image into luminance information using a perceptual quantizer electro-optical transfer function (PQ-EOTF), and adjust the luminance information according to the illuminance information to obtain luminance information of a second HDR image; a luminance analyzing sub-processor configured to analyze the luminance information of the second HDR image to calculate a high-luminance rate of occupancy of pixels having a target peak luminance or more of a display device in the second HDR image; a luminance mapping sub-processor configured to map the second HDR image to a third HDR image suitable for the display device using a mapping function changed according to the high-luminance rate; and an opto-electrical transfer function (OETF) sub-processor configured to convert the luminance information of the third HDR image into gray level information of a fourth HDR image using the PQ-OETF, and output the gray level information of the fourth HDR image. ### Claim 8 (depends on 7) The image processor according to claim 7, wherein the second HDR image includes a first luminance part and a second luminance part, and wherein the luminance mapping sub-processor: uses a first linear mapping function in the first luminance part having the target peak luminance or less of the second HDR image and uses a second non-linear mapping function in the second luminance part having the target peak luminance or more, when the high-luminance rate exceeds a threshold, and uses the first mapping function when the high-luminance rate is equal to or less than the threshold. ### Claim 9 (depends on 8) The image processor according to claim 8, wherein the luminance mapping sub-processor: increases luminance of the second luminance part of the second HDR image according to the second mapping function in a range between the target peak luminance of the display device and a maximum luminance of the display device, when the high-luminance rate exceeds the threshold, and maps the second luminance part of the second HDR image to the target peak luminance when the high-luminance rate is equal to or less than the threshold. ### Claim 10 (depends on 8) The image processor according to claim 8, wherein the luminance mapping sub-processor: performs conversion into input luminance normalized by dividing the luminance information of the second HDR image by maximum luminance of the display device before luminance-mapping the second HDR image to the third HDR image, and maps the input luminance to normalized output luminance of the display device using the first or second mapping function. ### Claim 11 (depends on 7) The image processor according to claim 7, wherein the EOTF sub-processor adjusts the luminance information according to the illuminance information by selecting a weight according to the illuminance information and applying the weight to the luminance, so as to obtain the luminance information of the second HDR image. ### Claim 12 (depends on 11) The image processor according to claim 11, further comprising: a memory configured to store weight information in association with illuminances in a look-up table which is to be used when selecting the weight. ### Claim 13 (depends on 7) The image processor according to claim 7, wherein the image processor is provided as part of a timing controller of the display device. ### Claim 14 A display device comprising: a display panel; an image processor; and a display panel driver configured to drive the display panel to display a high dynamic range (HDR) image received from the image processor, wherein the image processor comprises: an electro-optical transfer function (EOTF) sub-processor configured to receive illuminance information through an illuminance sensor, convert gray level information of a first HDR image into luminance information using a perceptual quantizer electro-optical transfer function (PQ-EOTF), and adjust the luminance information according to the illuminance information to obtain luminance information of a second HDR image; a luminance analyzing sub-processor configured to analyze the luminance information of the second HDR image to calculate a high-luminance rate of occupancy of pixels having target peak luminance or more of the display device in the second HDR image; a luminance mapping sub-processor configured to map the second HDR image to a third HDR image suitable for the display device using a mapping function changed according to the high-luminance rate; and an opto-electrical transfer function (OETF) sub-processor configured to convert the luminance information of the third HDR image into gray level information of a fourth HDR image using the PQ-OETF and to output the gray level information of the fourth HDR image. ### Claim 15 (depends on 14) The display device according to claim 14, wherein the second HDR image includes a first luminance part and a second luminance part, and wherein the luminance mapping sub-processor: uses a first linear mapping function in the first luminance part having the target peak luminance or less of the second HDR image and uses a second non-linear mapping function in the second luminance part having the target peak luminance or more, when the high-luminance rate exceeds a threshold, and uses the first mapping function when the high-luminance rate is equal to or less than the threshold. ### Claim 16 (depends on 15) The display device according to claim 15, wherein the luminance mapping sub-processor: increases luminance of the second luminance part of the second HDR image according to the second mapping function in a range between the target peak luminance of the display device and a maximum luminance of the display device, when the high-luminance rate exceeds the threshold, and maps the second luminance part of the second HDR image to the target peak luminance when the high-luminance rate is equal to or less than the threshold. ### Claim 17 (depends on 15) The display device according to claim 15, wherein the luminance mapping sub-processor: performs conversion into input luminance normalized by dividing the luminance information of the second HDR image by maximum luminance of the display device before luminance-mapping the second HDR image to the third HDR image, and maps the input luminance to normalized output luminance of the display device using the first or second mapping function. ### Claim 18 (depends on 14) The display device according to claim 14, wherein the EOTF sub-processor adjusts the luminance information according to the illuminance information by selecting a weight according to the illuminance information and applying the weight to the luminance, so as to obtain the luminance information of the second HDR image. ### Claim 19 (depends on 18) The display device according to claim 18, wherein the image processor is provided as part of a timing controller of the display device, or as an integrated circuit separate from the timing controller. ### Claim 20 (depends on 14) The display device according to claim 14, wherein the display panel is a liquid crystal display (LCD) panel or an organic light emitting diode (OLED) panel.