Patent ID: 7352494

Claim:
A pixel block data generating device for successively outputting pixel block data for each of pixel blocks that is a predetermined rectangular area in an image, said pixel block data including pixels of image data, the pixel block data generating device comprising: a memory for holding image data that have been input; a writing control portion for writing the image data in the memory; a reading control portion for successively reading the pixel block data from the memory for the each of the pixel blocks and outputting that pixel block data, wherein the writing control portion performs control in such a manner that the image data that have been newly input can be written in an area of the memory where the image data for pixels that form a portion of pixels of a given line of a plurality of lines are stored, each of said plurality of lines defined by pixels extending in a scanning line direction, and wherein, when a number of pixels on one line in a scanning line direction in the image is h (h is a natural number), the pixel block that is a predetermined rectangular area is a pixel block constituted by n pixels in the scanning line direction and m pixels in a direction perpendicular to the scanning line (n and m are natural numbers), the writing control portion and the reading control portion control a writing operation and a reading operation so as to repeatedly perform: a first writing operation of writing m lines of image data in a predetermined area of the memory in a predetermined order; a first reading operation of successively reading the written image data for the each of the pixel blocks including n pixels that are adjacent to one another in the scanning line direction, after the first writing operation is performed; a second writing operation of writing image data for each line in m lines of image data that are subsequent to the m lines of image data written in the first writing operation in the area of the memory where image data of each (h/m)/n pixel blocks have been read in the scanning line direction; and a second reading operation of successively reading the written image data for the each of the pixel blocks including n pixels that are adjacent to one another in the scanning line direction, after the second writing operation is performed.