# US 2018/0324428 A1 · Image processing apparatus and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324428 A1 - Document ID: US20180324428A1 - Status: Published application - Kind: A1 - Application number: 16/032,669 - Filed: 2018-07-11 - Published: 2018-11-08 - Earliest claimed: 2011-03-11 - Assignees: Sony Corporation - Applicants: Sony Corporation - Inventors: Kazushi SATO - Web page: https://patentgrep.com/patent/US20180324428A1 ## CPC - H04N 19/124: Quantisation - G06T 9/004: {Predictors, e.g. intraframe, interframe coding} - H04N 19/126: Details of normalisation or weighting functions, e.g. normalisation matrices or variable uniform quantisers - H04N 19/17: the unit being an image region, e.g. an object - H04N 19/463: by compressing encoding parameters before transmission - H04N 19/50: using predictive coding (H04N19/61 takes precedence) - H04N 19/593: involving spatial prediction techniques - H04N 19/61: in combination with predictive coding - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION - G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL ## Abstract An image processing apparatus and a method for improving the coding efficiency for a quantization parameter are provided. The method includes steps of setting a predicted quantization parameter for a current coding unit by using multiple quantization parameters which are set for multiple surrounding coding units located around the current coding unit which is target of coding processing, and setting a difference quantization parameter indicating a difference value between the quantization parameter which is set for the current coding unit and the predicted quantization parameter. ## Claims ### Claim 1 An image processing apparatus for decoding a bit stream, the image processing apparatus comprising: a decoding unit that decodes a bit stream including a difference quantization parameter which is a difference between a current quantization parameter which is set for a current coding unit and a predicted quantization parameter, with a size-variable coding unit as a unit of processing, and generates quantization data, the size-variable coding unit is obtained by recursively dividing a maximum coding unit of fixed size in a unit of sequence according to a quadtree structure; a predicted quantization parameter setting unit that sets a quantization parameter which is set for a surrounding coding unit located nearby which is not adjacent to the current coding unit as a predicted quantization parameter, when it is determined, based on a location of the current coding unit in a maximum current coding unit, that all adjacent coding units adjacent to the current coding unit are located outside the current maximum coding unit, and are not in an available state; a quantization parameter setting unit which sets the current quantization parameter by adding the difference quantization parameter to the predicted quantization parameter set by the predicted quantization parameter setting unit; and an inverse quantization unit that inversely quantizes quantized data generated by the decoding unit using the current quantization parameter set by the quantization parameter setting unit. ### Claim 2 (depends on 1) The image processing apparatus according to claim 1, further comprising a determination unit for determining whether the adjacent coding units are in an available state or not, based on the location of the current coding unit in the current maximum coding unit; wherein the predicted quantization parameter setting unit is configured to set the quantization parameter which is set for the surrounding coding unit as the predicted quantization parameter when the determination unit determines that all of the adjacent coding units are not in an available state. ### Claim 3 (depends on 2) The image processing apparatus according to claim 2, wherein the predicted quantization parameter setting unit sets the quantization parameter which is set for a coding unit previous to the current coding unit in a decoding processing sequence, as the predicted quantization parameter. ### Claim 4 (depends on 2) The image processing apparatus according to claim 2, wherein when the current coding unit is located at the front of the current maximum coding unit, the determination unit determines that all of the adjacent coding units are not in the available state. ### Claim 5 (depends on 4) The image processing apparatus according to claim 4, wherein the predicted quantization parameter setting unit sets the quantization parameter which is set for a coding unit located at a last coding unit in a previous maximum coding unit in decoding processing sequence, as the predicted quantization parameter, when the determination determines that the current coding unit is located at the front of the current maximum coding unit. ### Claim 6 (depends on 1) The image processing apparatus according to claim 1, wherein the predicted quantization parameter setting unit sets an average value of quantization parameters of the adjacent coding units set in the available state, as the predicted quantization parameter. ### Claim 7 (depends on 6) The image processing apparatus according to claim 6, wherein the adjacent coding units include a left adjacent coding unit adjacent to a left side of the current coding unit, and an upper adjacent coding unit adjacent to an upper side of the current coding unit; the predicted quantization parameter setting unit is configured to set an average value of a quantization parameter of the left adjacent coding unit set in the available state and a quantization parameter of the upper adjacent coding unit set in the available state, as the predicted quantization parameter ### Claim 8 An image processing method of an image processing apparatus for decoding a bit stream, which: decodes a bit stream including a difference quantization parameter which is a difference between a current quantization parameter which is set for a current coding unit and a predicted quantization parameter, with size-variable coding unit as a unit of processing, and generates quantization data, the size-variable coding unit is obtained by recursively dividing a maximum coding unit of fixed size in a unit of sequence according to a quadtree structure; sets a quantization parameter set for a surrounding coding unit located nearby which is not adjacent to the current coding unit as a predicted quantization parameter, when it is determined, based on a location of the current coding unit in a maximum current coding unit, that all adjacent coding units adjacent to the current coding unit are located outside the current maximum coding unit, and are not in an available state; sets the current quantization parameter by adding the difference quantization parameter to the predicted quantization parameter which has been set; and inversely quantizes the generated quantized data using the current quantization parameter which has been set. ### Claim 9 (depends on 8) The image processing method according to claim 8, which determines whether the adjacent coding units are in the available state or not based on the location of the current coding unit in the current maximum coding unit; and sets the quantization parameter which is set for the surrounding coding unit as the predicted quantization parameter when all of the adjacent coding units are not in the available state. ### Claim 10 (depends on 9) The image processing method according to claim 9, which sets the quantization parameter set for a coding unit previous to the current coding unit in a decoding processing sequence as the predicted quantization parameter. ### Claim 11 (depends on 9) The image processing method according to claim 9, wherein when the current coding unit is located at the front of the current maximum coding unit, determines that all of the adjacent coding units are not in the available state. ### Claim 12 (depends on 11) The image processing method according to claim 11, which sets the quantization parameter set for a coding unit located at a last coding unit in a previous maximum coding unit in decoding processing sequence as the predicted quantization parameter when it is determined that the current coding unit is located at the front of the current maximum coding unit. ### Claim 13 (depends on 8) The image processing method according to claim 8, which sets an average value of quantization parameters of the adjacent coding units set in the available state as the predicted quantization parameter. ### Claim 14 (depends on 13) The image processing method according to claim 13, wherein the adjacent coding units include a left adjacent coding unit adjacent to a left side of the current coding unit and an upper adjacent coding unit adjacent to an upper side of the current coding unit; the image processing method sets an average value of a quantization parameter of the left adjacent coding unit set in the available state and a quantization parameter of the upper adjacent coding unit set in the available state as the predicted quantization parameter