Patent ID: 8611658

Claim:
An image processing apparatus comprising: an input unit that inputs image data; an attribute information forming unit that forms attribute information for every pixel of the image data input by the input unit; a dividing unit that divides the image data input by the input unit into a plurality of blocks each having a preset size; a histogram forming unit that forms a histogram of colors which appear in a target block among the plurality of blocks divided by the dividing unit and of the number of pixels of each color; a first deciding unit that, in the case where an area of a region having a target color obtained by the histogram formed by the histogram forming unit is larger than a preset first threshold value, decides that the region having the target color is a significant region; a second deciding unit that, in the case where the area of the region having the target color obtained by the histogram formed by the histogram forming unit is equal to or smaller than the first threshold value and in the case where the region having the target color is located at a boundary of the target block and the attribute information formed by the attribute information forming unit for the pixel at the boundary in the region having the target color indicates a character attribute, decides that the region having the target color is a significant region; a substituting unit that, in the case where the region having the target color is not decided to be a significant region by either one of the first and second deciding units, substitutes a color of another region adjacent to the region having the target color within the target block for a color of the pixel in the region having the target color; and an integrating unit that, in the case where the region having the target color is decided to be a significant region by any one of the first and second deciding units and in the case where a chrominance difference between the region having the target color and another region, which is decided to be a significant region in another block adjacent to the target block, is equal to or less than a preset second threshold value, integrates the color of the region having the target color and a color of the other region decided to be the significant region in the other block.