Image coding device, image decoding device, image coding method, and image decoding method
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.
1. 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 partitioned into one or more coding blocks, the image decoding device comprising:
a coded data decoder to decode the coded data to acquire compressed data of a difference image associated with each one of the coding blocks and an offset,
a distortion remover to carry out a filtering process on a decoded image obtained by adding a prediction image to the difference image, and to remove a block distortion at a boundary between adjacent transform blocks of the decoded image, the transform block being for transforming the difference image; and
a memory storing decoded pixel values for outputting the decoded image on which the filtering process has been carried out,
wherein the distortion remover derives a value of a parameter specifying filtering strength as a default value for the offset according to a set of conditions including whether a coding mode corresponding to at least one of the adjacent transform blocks to which the filtering process is to be applied is intra prediction mode, wherein the offset is added to the value of the parameter in a process of selecting from different filtering processes.
2. 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 partitioned into one or more coding blocks, the image decoding method comprising:
decoding the coded data to acquire compressed data of a difference image associated with each one of the coding blocks and an offset,
carrying out a filtering process on a decoded image obtained by adding a prediction image to the difference image, and removing a block distortion at a boundary between adjacent transform blocks of the decoded image, the transform block being for transforming the difference image; and
storing decoded pixel values for outputting the decoded image on which the filtering process has been carried out,
wherein the filtering process derives a value of a parameter specifying filtering strength as a default value for the offset according to a set of conditions including whether a coding mode corresponding to at least one of the adjacent transform blocks to which the filtering process is to be applied is intra prediction mode, wherein the offset is added to the value of the parameter in a process of selecting from different filtering processes.