IMAGE PROCESSING APPARATUS AND IMAGE PROCESSING METHOD

摘要

PROBLEM TO BE SOLVED: To enable more accurate detection of a quantization factor used in previous encoding in back search.

SOLUTION: A DCT section 32 performs orthogonal transform of image data to generate transform coefficients. A back search section 33 detects a quantization factor used in previous encoding using the transform coefficients and if the quantization factor cannot be detected from the transform coefficients of luminance components of the image data, determines a quantization factor detected from the transform coefficients of color difference components as the quantization factor used in the previous encoding. A quantization setting section 42 selects a quantization factor detected by a pre-encoding section 20 if the quantization factor cannot be detected by back search or a generated code amount in encoding using the detected quantization factor exceeds a target code amount, and selects the quantization factor detected by the back search if the generated code amount is equal to or less than the target code amount. An encoding section 50 performs encoding based on the selected quantization factor.

COPYRIGHT: (C)2012,JPO&INPIT