Patent ID: 6212236
Filing Date: 2001-04-03
Classification: H04N

Abstract:
An image decoding apparatus for decoding coded data to generate moving pictures, the image decoding apparatus comprising:extracting means for extracting a coded unit image from the coded data, wherein the coded unit image includes difference information which indicates whether an original unit image of the coded unit image is equal to a reference unit image which is a part of a frame picture having been decoded, and, during a predictive coding process, the original unit image is transformed into the coded unit image which includes difference values between pixel values of the original unit image and pixel values of the reference unit image when the difference information indicates that the original unit image is different from the reference unit image, wherein the coded unit image including the difference values is also called a coded difference unit image, the original unit image and the reference unit image each having a same, predetermined number of pixels;difference decoding means for decoding the coded difference unit image including the difference values to generate a difference unit image;preventing means for preventing the difference decoding means from generating the difference unit image when the extracted difference information indicates that the original unit image of the coded unit image is equal to the reference unit image;first constant generating means for generating a first constant image which is composed of constants ""0"";first image selecting means for selecting the first constant image when the difference information indicates that the original unit image is equal to the reference unit image and selecting the difference unit image when the difference information indicates that the original unit image is different from the reference unit image; andimage restoring means for restoring the original unit image by adding a result selected by the first image selecting means to the reference unit image.