Patent ID: 8406543
Filing Date: 2013-03-26
Classification: H04N

Abstract:
1. An image decoding apparatus comprising: an input section configured to input coded image data wherein each block obtained by dividing an image into a plurality of blocks is expressed by a plurality of representative values that represent gradation value of a pixel pertaining to the block, and label information that shows which of each pixel pertaining to the block corresponds to which of the representative value; a Block Truncation Coding BTC decoding section configured to perform a first-phase decoding process to decode the coded image data inputted from the input section; and a block noise reduction process section configured to perform a second-phase decoding process to reduce block noise of the image data having been decoded by the BTC decoding section; wherein when each of the pixels in a focused block is decoded according to the representative value, and when a size in a range of distribution of the representative values in the focused block is equal to or greater than a prescribed multiple times the size in the range of distribution of the representative values in an adjacent block, out of the representative values of the focused block, a representative value whose difference from an intermediate value or a mean value of the representative values of the adjacent block is equal to or less than a first threshold value is assumed to be an adjusted representative value, and the block noise reduction section is configured to provide a variance to the decoded value of the pixel possessing the label information corresponding to the adjusted representative value to reduce block noise of the image data.