PURPOSE: To improve the coding efficiency by applying variable length coding to significant/insignificant information while the information is collected every M pieces of large blocks.
CONSTITUTION: A difference signal series 203 is obtained from an inputted signal series 202 by subtracting a preceding signal series 204 on the same position of a picture stored in a frame memory 103 from the series 202. Then a block coding device 102 identifies significance/insignificance of the difference signal series based on a threshold level 300 to apply block coding only to the difference signal coding signal 203 of a significant block. A block decoder 104 decodes a block coding signal 206 to obtain a decoded difference signal series 207 and adds it to the preceding signal series 204 to obtain a decoded signal series 208. The decoded signal series 208 is fed to the frame memory 103. On the other hand, A significance/insignificance identification signal 205 is integrated further for each of M-sets in a block processing circuit and a pattern discrimination circuit discriminates whether a consecutive number of the integrated information sets is to be coded or their combinations are to be coded.
UESAWA ISAO
ITO ATSUSHI
