PURPOSE: To store the images with high picture quality and at the rational cost by making great account of the low band components when one to ten million picture elements re coded in a standard coding system and setting the coding compression ratio at 1/8-1/80.
CONSTITUTION: A DCT part 102 applies the discrete cosine transformation to a given image part every (8×8) matrices. At this time, the matrices are arranged so that the horizontal space frequency is set at a low and high levels at the left and right sides respectively and that the vertical space frequency is set at low and high levels at the upper and lower sides respectively. Then the numerical value set at the point in the vicinity of the upper left corner represents the low bands. A quantizing part 103 quantizes the output of the part 102 based on a quantization table 104. When the relationship is tested among the compression ratio, the number of picture elements and the picture quality, the substantially satisfactory picture quality is secured with a million or more number of picture elements and the compression rate of 1/64. Then one to ten million picture elements and the compression ratio 1/8-1/80 are defined best in regard of the memory cost.
Tohru Tekata
Akitsu Akutsu
