IMAGE QUALITY EVALUATION VALUE CALCULATION METHOD AND IMAGE QUALITY EVALUATION VALUE CALCULATION APPARATUS

摘要

PPROBLEM TO BE SOLVED: To provide an image quality evaluation value calculation method capable of simply obtaining an image quality evaluation value of an image photographed by an imaging apparatus in a short time. PSOLUTION: Original image data are divided into a plurality of blocks, DCT conversion is applied to the blocks to obtain transform coefficients, the blocks including many high frequency components are used for image quality evaluation value calculation blocks, transform coefficients of each of a plurality of the blocks obtained by the DCT conversion are compressed by using a prescribed quantization table, and each of the quantized transform coefficients subjected to compression is expanded by using the quantization table used at the compression. Then inverse DCT conversion is applied to the transform coefficients respectively corresponding to the image quality evaluation value calculation block and surrounding adjacent blocks thereto among a plurality of the transform coefficients decoded by the expansion, a difference between a pixel value of the image circumferential edge part of the image quality evaluation value calculation block and a pixel value of the image circumferential edge of the surrounding adjacent blocks in contact with the image quality evaluation value calculation block is obtained and the result is used for the image quality evaluation value with respect to the prescribed quantization table. PCOPYRIGHT: (C)2005,JPO&NCIPI