Image Processing Apparatus and Image Processing Method for Compressing Image Data by Combining Spatial Frequency Conversion, Quantization, and Entropy Coding

摘要

An image processing apparatus is configured for compressing image data by combining spatial frequency conversion, quantization, and entropy coding. The apparatus includes a block division section, a spatial frequency conversion section, a quantization section, an encoding section, and a selection section. The encoding section generates code data by performing the entropy coding for each of a plurality of change candidate values. The values include a value of quantized data in a pixel block after performing the spatial frequency conversion and peripheral values within a predetermined range. The selection section selects a change value of the quantized data from the plurality of change candidate values based on a size of the code data of each of the plurality of change candidate values, and sets the code data corresponding to the selected change value as the code data.