Image encoding and decoding method and apparatus, and recording medium in which program therefor is recorded

摘要

The invention relates to an image encoding/decoding method, apparatus thereof and a recording medium in which a program therefor is recorded, whereby the encoding/decoding can be obtained with high image quality at high speed. In an image encoding method which comprises producing a DC image composed of each block mean value by dividing an image data per B pixel into a block, making a part of said DC image a DC nest, and where the differential vector which is obtained by separating the DC value DCJ from the pixel block to be encoded is over an allowable value Z, calculating one or more orthogonal basis ( alpha k ), to which the differential vector is approximated, by the adaptive orthogonal transform (AOT) using the DC nest, each of the lowest n (n = log2 B) bits of base extraction blocks which are down-sampled from the DC nest is set to 0 . Further, base extraction vectors are produced by separating a block mean value ai from the base extraction blocks .