Patent ID: 8031955

Claim:
An image processing apparatus, comprising: a block setting unit that sets a block of a plurality of blocks having a fixed size to inputted image data, the set block including a plurality of sub-blocks, with each sub-block including a pixel value; a determining unit that determines whether or not at least two of the sub-blocks included in the set block are filled with a single pixel value, wherein the determining unit comprises: a difference value evaluating unit that calculates a difference value between each pair of the plurality of sub-blocks included in the set block pixel values, and evaluates the plurality of calculated difference values; and a region determining unit that determines at least two of the sub-blocks, among the sub-blocks included in the set block, that should be filled with the single pixel value on the basis of a result of the evaluation for each pair of the plurality of sub-blocks by the difference value evaluating unit, a pixel value replacing unit that replaces the sub-blocks included in the set block by the single pixel value according to a result of the determination by the determining unit, wherein the pixel value replacing unit replaces the image region determined by the region determining unit by the single pixel value; and a hierarchical process controller that instructs the block setting unit to set a broader block including a plurality of set blocks.