Patent ID: 7953296

Claim:
An image processing apparatus comprising: an input unit which inputs image data having a plurality of tiles, each tile having a plurality of pixels; a resolution conversion unit which converts image data of an input tile into a resolution lower than that of the image data; a first calculating unit which calculates a difference between image data after conversion by said resolution conversion unit and image data of a tile before resolution conversion as a resolution conversion error; a second calculating unit which calculates a run ratio at which pixels having the same color continue in the image data of the tile; a third calculating unit which calculates a two-colors ratio which is a ratio at which the number of colors in a tile of interest becomes two by counting the number of surrounding pixel groups which are located near a pixel position of interest, which include two colors during raster scanning of the image data of the tile; and a determination unit which determines, on the basis of information calculated by said first, said second, and said third calculating units, whether an image of a tile of interest has a characteristic that (a) the calculated image data difference is large, (b) the run ratio is small, and (c) the two-colors ratio is large.