Image coding device, image decoding device, image coding method, and image decoding method
AssigneeMitsubishi Electric Corporation
InventorsShunichi SEKIGUCHI, Kazuo SUGIMOTO, Hiroharu SAKATE, Tokumichi MURAKAMI, Akira MINEZAWA
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Abstract
When removing a block distortion occurring in a local decoded image, a loop filtering part 11 of an image coding device carries out a filtering process on each of signal components (a luminance signal component and color difference signal components) after setting the intensity of a filter for removing the block distortion for each of the signal components according to a coding mode (an intra coding mode or an inter coding mode) selected by a coding controlling part 1.
Claims3
An image decoding device that carries out a decoding process on a coded data obtained by performing a block based coding process on an image, said image decoding device comprising:
- a decoding unit for decoding the coded data to acquire compressed data of a difference image and a coding mode associated with each of coding blocks, the coding mode indicating a prediction mode and prediction blocks in each of the coding blocks;
- a prediction image generating unit for carrying out a prediction process for each of the coding blocks according to the coding mode to generate a prediction image of each of coding blocks;
- a decoded image generating unit for adding a decompressed difference image to the prediction image for each of the blocks to generate a decoded image;
- and
- a distortion removing unit for carrying out a filtering process on the decoded image to remove a block distortion occurring at a boundary between adjacent prediction blocks of the decoded image,
- wherein the distortion removing unit derives a parameter specifying filtering strength according to a set of conditions including whether the coding mode corresponding to at least one of the adjacent prediction blocks to which the filtering process is to be applied is intra prediction mode, a value of the parameter being used in a process of selecting from different filtering processes.
An image decoding method that carries out a decoding process on a coded data obtained by performing a block based coding process on an image, said image decoding method comprising:
- a decoding processing step for decoding the coded data to acquire compressed data of a difference image and a coding mode associated with each of coding blocks, the coding mode indicating a prediction mode and prediction blocks in each of the coding blocks;
- a prediction image generation processing step for carrying out a prediction process on each of the coding blocks to generate a prediction image;
- a decoded image generation processing step for adding a decompressed difference image to the prediction image for each of the coding blocks to generate a decoded image;
- and
- a distortion removal processing step of for carrying out a filtering process on the decoded image to remove a block distortion occurring at a boundary between adjacent prediction blocks of the decoded image,
- wherein in said distortion removal processing step, when removing a block distortion occurring in said decoded image, a parameter specifying filtering strength is derived according to a set of conditions including whether the coding mode corresponding to at least one of the adjacent prediction blocks to which the filtering process is to be applied is intra prediction mode, a value of the parameter being used in a process of selecting from different filtering processes.
A non-transitory computer readable medium comprising coded data for each of a plurality of coding blocks, said coded data including:
- information specifying a coding mode;
- and
- compressed data of a difference image,
- wherein the non-transitory computer readable medium is prepared by a process comprising a steps of:
- dividing an image into the plurality of coding blocks each of which is a unit for coding process;
- carrying out a prediction process on each of the coding blocks to generate a prediction image according to said coding mode determined for each of the coding blocks;
- compressing a difference between each of the coding blocks and the prediction image for each of the coding blocks to output said compressed data of said difference image;
- decompressing the compressed data of the difference image and adding a decompressed difference image to the prediction image to generate a local decoded image;
- and
- carrying out a filtering process on the local decoded image to remove a block distortion occurring at a boundary between adjacent coding blocks of the local decoded image,
- wherein, in said coded data for each of the plurality of coding blocks, said information specifying said coding mode indicates whether the coding mode at the corresponding coding block is intra coding or inter coding,
- wherein a decoder derives a parameter specifying filtering strength according to a set of conditions including whether the coding mode of at least one of the adjacent coding blocks to which the filtering process is to be applied is intra coding based on said information, a value of the parameter being used in a process of selecting from among different filtering processes.
Dependencies are inferred from the claim text.