COLOR IMAGE CODER

摘要

PURPOSE: To obtain a color image coder in which deterioration in image quantity is reduced by selecting a block whose color quality deterioration of a color signal is easily recognized through setting a simple threshold level so as to decrease the quantization width of the selected block. CONSTITUTION: An absolute value of a difference between a mean value of picture element values in each block and an achromatic color level of a color difference signal is calculated. Whether or not a maximum value of the absolute value is larger than a prescribed threshold level is discriminated by a color difference signal check device 15 and a quantization controller 16 decides the quantization width by using the discrimination result and a code string length counted by a generated code amount counter 17.