# US 12,182,979 B2 · Brightness and contrast enhancement for video > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,182,979 B2 - Document ID: US12182979B2 - Status: Granted - Kind: B2 - Application number: 18/474,936 - Filed: 2023-09-26 - Published: 2024-03-07 - Granted: 2024-12-31 - Earliest claimed: 2020-03-18 - Assignees: Intel Corporation - Applicants: Intel Corporation - Inventors: Ya-Ti Peng; Yi-Jen Chiu - Web page: https://patentgrep.com/patent/US12182979B2 ## CPC - G06T 5/90: Dynamic range modification of images or parts thereof - G06T 5/94: based on local image properties, e.g. for local contrast enhancement - G06T 5/40: using histogram techniques - G06T 7/136: involving thresholding - H04N 9/646: {for image enhancement, e.g. vertical detail restoration, cross-colour elimination, contour correction, chrominance trapping filters} - H04N 9/68: for controlling the amplitude of colour signals, e.g. automatic chroma control circuits (H04N9/71, H04N9/73 take precedence; camera processing pipelines for controlling the colour saturation of colour signals H04N23/86) - G06T 2207/10024: Color image - G06T 2207/20008: Globally adaptive - G06T 2207/20012: Locally adaptive - G06T 2207/20208: High dynamic range [HDR] image processing - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract Methods and systems to improve a visual perception of dark scenes in video. An example device includes one or more processors to receive a frame of video segmented into a plurality of sub-regions. A local luminance histogram is generated for each sub-region. A global luminance histogram is generated for the entire frame of video and a global tone mapping curve is generated based on the global luminance histogram. A tone mapping LUT is generated for each sub-region based on the global tone mapping curve and the corresponding local luminance histogram for the sub-region. The frame of video is then modified using the tone mapping LUTs generated for each sub-region and sent to an output device. ## Claims ### Claim 1 An apparatus comprising: interface circuitry; machine-readable instructions; and at least one processor circuit to be programmed by the machine-readable instructions to: generate histograms based on a frame of video divided into regions, respective ones of the regions corresponding to respective ones of the histograms having luminance values of corresponding pixels; generate a data structure based on a sum of the histograms; and apply brightness adjustment values to corresponding ones of the pixels based on a tone mapping curve, the tone mapping curve based on the data structure. ### Claim 2 (depends on 1) The apparatus as defined in claim 1, wherein the programmable circuitry is to derive a list of look up tables (LUTs) to transfer the luminance values of the histograms to a contrast adjustment value. ### Claim 3 (depends on 2) The apparatus as defined in claim 2, wherein the programmable circuitry is to apply a contrast compensation function to derive the list of LUTs. ### Claim 4 (depends on 2) The apparatus as defined in claim 2, wherein the LUTs correspond to respective ones of the divided regions. ### Claim 5 (depends on 4) The apparatus as defined in claim 4, wherein the programmable circuitry is to reduce edge artifacts by generating a first LUT of the list of LUTs by calculating a weighted average of ones of the LUTs adjacent to the first LUT. ### Claim 6 (depends on 1) The apparatus as defined in claim 1, wherein the programmable circuitry is to modify the frame of video based on the brightness adjustment values. ### Claim 7 (depends on 6) The apparatus as defined in claim 6, wherein the programmable circuitry is to send the modified frame of video to an output device. ### Claim 8 At least one non-transitory machine-readable medium comprising machine-readable instructions to cause at least one processor circuit to: generate histograms based on a frame of video divided into regions, respective ones of the regions corresponding to respective ones of the histograms having luminance values of corresponding pixels; generate a data structure based on a sum of the histograms; and apply brightness adjustment values to corresponding ones of the pixels based on a tone mapping curve, the tone mapping curve based on the data structure. ### Claim 9 (depends on 8) The at least one non-transitory machine-readable storage medium of claim 8, wherein the machine-readable instructions cause the at least one processor circuit to derive a list of look up tables (LUTs) to transfer the luminance values of the histograms to a contrast adjustment value. ### Claim 10 (depends on 9) The at least one non-transitory machine-readable storage medium of claim 9, wherein the machine-readable instructions cause the at least one processor circuit to apply a contrast compensation function to derive the list of LUTs. ### Claim 11 (depends on 9) The at least one non-transitory machine-readable medium of claim 9, wherein the LUTs correspond to respective ones of the regions. ### Claim 12 (depends on 11) The at least one non-transitory machine-readable storage device or storage disk of claim 11, wherein the machine-readable instructions cause the at least one processor circuit to reduce edge artifacts by generating a first LUT of the list of LUTs by calculating a weighted average of ones of the LUTs adjacent to the first LUT. ### Claim 13 (depends on 8) The at least one non-transitory machine-readable storage device or storage disk of claim 8, wherein the machine-readable instructions cause the at least one processor circuit to modify the frame of video based on the brightness adjustment values. ### Claim 14 A method to improve a visual perception of pixels, the method comprising: generating, by at least one processor circuit programmed by at least one instruction, histograms based on a frame of video divided into regions, respective ones of the regions corresponding to respective ones of the histograms having luminance values of corresponding pixels; generating, by one or more of the at least one processor circuit, a data structure based on a sum of the histograms; and improving, by one or more of the at least one processor circuit, the visual perception of the pixels by applying brightness adjustment values to corresponding ones of the pixels based on a tone mapping curve, the tone mapping curve based on the data structure. ### Claim 15 (depends on 14) The method as defined in claim 14, further including deriving a list of look up tables (LUTs) to transfer the luminance values of the histograms to a contrast adjustment value. ### Claim 16 (depends on 15) The method as defined in claim 15, further including applying a contrast compensation function to derive the list of LUTs. ### Claim 17 (depends on 15) The method as defined in claim 15, wherein the LUTs correspond to respective ones of the regions.