OPTIMIZING METHOD AND SYSTEM FOR QUANTIZATION TABLE FOR IMAGE CODING, AND RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To obtain an optimizing method and its system for a quantization table in image coding for optimizing quantization at a high compression rate with excellent image quality and to obtain a recording medium to record its processing program. SOLUTION: A coding section 3 uses a quantization table to encode compressed image data to be coded into coded image data, and a decoding section 4 uses the quantization table to decode the coded image data into decoded image data. Then an image compression rate calculation section 8 calculates a compression rate for the compressed image data and the coded image data, and an image quality evaluation section 9 calculates an image quality evaluation scale resulting from evaluating the image quality of the decoded image data in comparison with that of the compressed image data. A controller 21 of a high dimension algorithm arithmetic section 1 updates the quantization table based on the value of the an evaluation function based on the arithmetic value and optimizes the quantization table by repeating the processing of each section above for a prescribed number of times.