# US 11,451,768 B2 · Method for image processing and apparatus for implementing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,768 B2 - Document ID: US11451768B2 - Status: Granted - Kind: B2 - Application number: 16/815,567 - Filed: 2020-03-11 - Published: 2020-09-17 - Granted: 2022-09-20 - Earliest claimed: 2019-03-12 - Assignees: Ateme - Applicants: Ateme - Inventors: Elie Mora; Mohsen Abdoli; Thomas Guionnet - Web page: https://patentgrep.com/patent/US11451768B2 ## CPC - H04N 19/103: Selection of coding mode or of prediction mode - H04N 19/11: among a plurality of spatial predictive coding modes - G06F 17/16: Matrix or vector computation {, e.g. matrix-matrix or matrix-vector multiplication, matrix factorization (matrix transposition G06F7/78)} - G06N 7/01: Probabilistic graphical models, e.g. probabilistic networks - G06T 7/11: Region-based segmentation - G06T 7/90: Determination of colour characteristics - H04N 19/136: Incoming video signal characteristics or properties - H04N 19/176: the region being a block, e.g. a macroblock - H04N 19/196: being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters (processing of motion vectors H04N19/513) - H04N 19/593: involving spatial prediction techniques - G06T 2207/10016: Video; Image sequence - H04N 19/105: Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction - H04N 19/14: Coding unit complexity, e.g. amount of activity or edge presence estimation (H04N19/146 takes precedence) - H04N 19/157: Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract A method of processing an image divided into a plurality of pixel blocks which are processed according to a processing sequence is provided, which comprises, for a current pixel block: determining an application area comprising a set of pixels in blocks preceding the current block in the processing sequence; performing a gradient analysis on at least one pixel of the application area; selecting at least two intra prediction video coding modes among a plurality of intra prediction video coding modes usable for processing the current pixel block, wherein at least one of the selected intra prediction video coding modes is selected based on the gradient analysis; determining a plurality of predictors of the current pixel block based on the at least two selected intra prediction video coding modes; and generating a predictor of the current pixel block based on the determined plurality of predictors. ## Claims ### Claim 1 A method of processing an image divided into a plurality of pixel blocks which are processed according to a processing sequence, the method comprising, for a current pixel block: determining an application area comprising a set of pixels in blocks preceding the current block in the processing sequence; performing a gradient analysis on at least one pixel of the application area; selecting at least two intra prediction video coding modes among a plurality of intra prediction video coding modes usable for processing the current pixel block, wherein at least one of the selected intra prediction video coding modes is selected based on the gradient analysis; determining a plurality of predictors of the current pixel block respectively based on the at least two selected intra prediction video coding modes; and generating a predictor of the current pixel block based on the determined plurality of predictors; wherein the performing the gradient analysis comprises: for at least one pixel of the application area, computing a gradient representing a directional change of an intensity at the pixel, and wherein the selecting the at least one intra prediction video coding mode based on the gradient analysis comprises: for the at least one pixel of the application area, mapping the computed gradient to an intra prediction mode among the plurality of intra prediction video coding modes. ### Claim 2 (depends on 1) The method according to claim 1, further comprising: determining an application area comprising a plurality of pixels in blocks preceding the current block in the processing sequence; and performing a gradient analysis on at least two pixels of the application area. ### Claim 3 (depends on 1) The method according to claim 1, further comprising: determining weights that are respectively associated with the selected intra prediction video coding modes, and combining the determined predictors using the determined weights. ### Claim 4 (depends on 1) The method according to claim 1, wherein the at least two intra prediction video coding modes are selected based on the gradient analysis. ### Claim 5 (depends on 1) The method according to claim 1, further comprising: discarding at least one duplicate in the selected intra prediction video coding modes. ### Claim 6 (depends on 5) The method according to claim 5, wherein a plurality of intra prediction video coding modes are selected based on the gradient analysis, the method further comprising: replacing a discarded intra prediction video coding mode that was selected based on the gradient analysis, by selecting another intra prediction video coding mode based on the gradient analysis. ### Claim 7 (depends on 1) The method according to claim 1, wherein a number of intra prediction video coding modes selected based on the gradient analysis is based on a size of the current pixel block. ### Claim 8 (depends on 1) The method according to claim 1, performed by a processor of an image encoder, and further comprising, at the image encoder: encoding, via the processor, the current pixel block according to the at least one intra prediction video coding mode selected based on the gradient analysis. ### Claim 9 (depends on 1) The method according to claim 1, performed by a processor of an image decoder, and further comprising, at the image decoder: decoding, via the processor, the current pixel block according to the at least one intra prediction video coding mode selected based on the gradient analysis. ### Claim 10 (depends on 8) The method according to claim 8, wherein the at least one intra prediction video coding mode selected based on the gradient analysis is used at the image encoder for encoding the current block, and is used at the decoder for decoding the current block. ### Claim 11 (depends on 1) The method according to claim 1, wherein the performing the gradient analysis further comprises: computing a first gradient value representing an estimate magnitude of the directional change of the intensity at the at least one pixel, and a second gradient value representing an estimate orientation of the directional change of the intensity at the at least one pixel. ### Claim 12 (depends on 1) The method according to claim 1, wherein the performing the gradient analysis comprises: generating respective estimates of derivatives of an intensity level at the at least one pixel in the horizontal and vertical directions by performing a convolution of a source matrix of pixels of the image with horizontal and vertical filter matrices, respectively. ### Claim 13 (depends on 11) The method according to claim 11, wherein the mapping is performed by mapping the second gradient value to a directional intra prediction mode among the plurality of intra prediction video coding modes. ### Claim 14 (depends on 1) The method according to claim 1, wherein the selecting the at least one intra prediction video coding mode based on the gradient analysis further comprises: determining respective weight values for several intra prediction modes among the plurality of intra prediction video coding modes, based on gradients computed for pixels of the application area. ### Claim 15 (depends on 14) The method according to claim 14, wherein the weight value for an intra prediction video coding mode is determined based on the one or more computed gradient mapped to the intra prediction video coding mode. ### Claim 16 (depends on 14) The method according to claim 14, wherein at least one of the at least one intra prediction video coding mode selected based on the gradient analysis is selected based on its weight value. ### Claim 17 An apparatus, the apparatus comprising a processor and a memory operatively coupled to the processor, wherein the apparatus is configured to perform a method of processing an image divided into a plurality of pixel blocks which are processed according to a processing sequence, the method comprising, for a current pixel block: determining an application area comprising a set of pixels in blocks preceding the current block in the processing sequence; performing a gradient analysis on at least one pixel of the application area; selecting at least two intra prediction video coding modes among a plurality of intra prediction video coding modes usable for processing the current pixel block, wherein at least one of the selected intra prediction video coding modes is selected based on the gradient analysis; determining a plurality of predictors of the current pixel block based on the at least two selected intra prediction video coding modes; and generating a predictor of the current pixel block based on the determined plurality of predictors; wherein the performing the gradient analysis comprises: for at least one pixel of the application area, computing a gradient representing a directional change of an intensity at the pixel, and wherein the selecting the at least one intra prediction video coding mode based on the gradient analysis comprises: for the at least one pixel of the application area, mapping the computed gradient to an intra prediction mode among the plurality of intra prediction video coding modes. ### Claim 18 A non-transitory computer-readable medium encoded with executable instructions which, when executed, causes an apparatus comprising a processor operatively coupled with a memory, to perform a method of processing an image divided into a plurality of pixel blocks which are processed according to a processing sequence, the method comprising, for a current pixel block: determining an application area comprising a set of pixels in blocks preceding the current block in the processing sequence; performing a gradient analysis on at least one pixel of the application area; selecting at least two intra prediction video coding modes among a plurality of intra prediction video coding modes usable for processing the current pixel block, wherein at least one of the selected intra prediction video coding modes is selected based on the gradient analysis; determining a plurality of predictors of the current pixel block based on the at least two selected intra prediction video coding modes; and generating a predictor of the current pixel block based on the determined plurality of predictors; wherein the performing the gradient analysis comprises: for at least one pixel of the application area, computing a gradient representing a directional change of an intensity at the pixel, and wherein the selecting the at least one intra prediction video coding mode based on the gradient analysis comprises: for the at least one pixel of the application area, mapping the computed gradient to an intra prediction mode among the plurality of intra prediction video coding modes.