| 摘要 |
PROBLEM TO BE SOLVED: To extract a white background area with high precision by using all information of R, G, and B by dividing color image data into multiple areas and deciding whether or not each area is a white background area according to the feature quantities of the respective divided areas. SOLUTION: An image input part 1 such as a scanner inputs a color image and generates planes (e.g. image with 256 gradations quantized with 8 bits) of R, G, and B signals. An area division part 2 divides each of the plane of R, G, and B into the same areas (character area, pattern area, etc.), according to the features of the image. A part 3 for binarization by areas performs dynamic binarization by the areas of the respective planes. Consequently, threshold values as many as the areas are found. A part 4 for feature quantity calculation by the areas finds the mean value of pixel density above a binarization threshold in an area to obtain a feature quantity. A white background decision part 5 decides whether or not an area is a white background area on the basis of the calculated mean of the density of RGB.
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