Patent ID: 8494261

Claim:
An image processing apparatus comprising: a tile division unit configured to divide input image data into tiles each including a predetermined number of pixels; a block division unit configured to divide each of the tiles, that are divided by said tile division unit, into blocks each having a size of M×N pixels; a pattern flag specification unit configured to sequentially determine, as a processing object, each of the blocks divided by said block division unit, and to compare color data of respective pixels in the block that is the processing object, thereby specifying a pattern flag indicating an arrangement pattern of color data included in each of the blocks; an extraction unit configured to extract first color data from a pixel at a predefined position in each of the blocks, and further to extract, from a block for which it is determined that the number of color data included in the block is one of 2 to 4, second color data to fourth color data corresponding to the arrangement pattern defined in the specified pattern flag; a first holding unit configured to hold, in a memory, the pattern flag of each of the blocks, that is specified by said pattern flag specification unit, the first color data extracted by said extraction unit, and the second color data to fourth color data extracted by said extraction unit; an address specification unit configured to specify addresses in the memory, at which the first color data and the second color data to fourth color data in a block to be composed are held, based on composite image data to be composed; and a composition unit configured to rewrite the first color data and the second color data to fourth color data in the block to be composed, that are held at the addresses specified by said address specification unit, based on the color data of the composite image data.