Patent US 5,659,636

An image information coding apparatus includes cut-out unit for cutting out image information into blocks each having a predetermined size, transforming unit for preprocessing to generate frequency information from each block, coding unit for separating the frequency information into a first frequency component relating to an average value of the block and a second frequency component different form the first frequency component and for coding the first and second frequency components independently. The coding unit includes scalar quantization means for performing scalar quantization on the frequency information, extracting unit for extracting zero information from the scalar quantized frequency information which includes the second frequency components, and zero coding unit for coding the zero information. The zero coding unit codes the zero information in accordance with a characteristic of the block such that a number of zero elements after coding is not smaller than a number of zero elements before coding and such that a plurality of zero elements are collectively coded.