GRAY SCALE LEVEL REDUCTION METHOD, APPARATUS, AND INTEGRATED CIRCUIT, AND COMPUTER READABLE MEDIUM STORING GRAY SCALE REDUCTION PROGRAM

A gray scale reduction method or apparatus reduces required memory capacity for storing gray scale as compared with conventional gray scale reduction methods. The gray scale reduction apparatus performs quantization error scattering of input gray level data of an input image. Data produced by the quantization error scattering is filtered after completing the quantization error scattering.