Coding and decoding methods for a picture signal using overlapping blocks having variable block sizes and apparatuses therefor

摘要

The described method and apparatus for coding and decoding a bidimensional signal of the present invention comprises at a coding side means for dividing a bidimensional input signal into rectangular blocks of a plurality of sizes, providing window functions h_AM (m) and h_BN (n) on a direction and block size basis, means for calculating, assuming that a block of interest has an M x N size, a transformed signal Xp (k, i) from input signals xp (m, n) by means of a particular transform equation. The block division information and the transformed signals are transmitted to a decoding side. At the decoding side window functions f_AM (m) and f_BN (n) corresponding to the window functions h_AM (m) and h_BN (n), respectively, are provided for calculating, when a block size of the transformed signals sent from the coding side is M x N, inverse-transformed signals yp (m, n) of 2M x 2N points from the transformed signals. The inverse-transformed signals are arranged according to the block division information sent from the coding side, and the inverse-transformed signals are added, in a portion where a plurality of blocks overlap to produce a decoded signal. This system splits a bidimensional picture signal into picture blocks and is capable of decoding an input signal correctly even when blocks overlap and have a variable block size.