Patent ID: 7145693

Claim:
An image processing apparatus comprising: input means for inputting a luminance signals of pixels which are components of a color multi-value image; color attribute determination means for determining whether each pixel in the color multi-value image is white, black or color on the basis of a luminance signal of the pixel and outputting a determination result; storage means for storing the color attribute of the pixels which are included in two lines in the color multi-value image; first counting means comprising first, second and third window counting means, wherein said first window counting means counts the number of first windows including a color pixel of interest and at lease one black pixel around the pixel of interest, where each first window has a size of 2×n pixels set on the two lines, said second window counting means counts the number of second windows that include no black pixel and that include two color pixels that are continuous in a vertical direction except both end four pixels in the window, where each second window has a size of 2×m (where m>n) pixels set on the two lines, and said third window counting means counts the number of third windows, where each third window has only color pixels in the second window; second counting means for counting the number of the first, second and third windows in a first band area including a plurality of lines in the color multi-value image; calculation means for calculating a parameter indicating an image attribute of a second band area, whose size is two times that of the first band area, on the basis of results provided by said first and second counting means; attribute determination means for determining an image attribute of the second band area on the basis of the results provided by said first and second counting means and the parameter calculated by said calculation means; and final determination means for determining an image attribute of a third band area on the basis of the image attributes of two second band areas, where the third band area is an area of overlap of two second band areas and is the same size as the first band area.