IMAGE ENCODER AND IMAGE DECODER

摘要

PROBLEM TO BE SOLVED: To solve the problem that a memory and a circuit scale for calculation are increased with the increase of the number of symbols since the occurring probability of all the symbols has to be calculated always. SOLUTION: An image encoder counts the number of continuous input times of the same symbol to a variable length encoding part 2, specifies the symbol maximizing the number of continuous input times and updates an adaptive encoded word table 1 so that an encoded word corresponding to the symbol becomes the shortest encoded word. A image decoder counts the number of continuous output times of the same symbol by a variable length decoding part 6, specifies the symbol maximizing the number of continuous output times and updates an adaptive encoded word table 5 so that an encoded word corresponding to the symbol becomes the shortest encoded word.