摘要 |
An image processing apparatus includes: a quadrangular or polygonal area setting unit that sets a quadrangular or polygonal area that surrounds a group of pixels that has predetermined characteristics for image data; a background setting unit that measures frequency distribution of tone values outside the quadrangular or polygonal area, measures a brightest tone value B in a margin range, which is a range of tone values in which the image data is distributed significantly, measures a most frequent value M in the margin range, and sets a background range, which is a range that includes the most frequent value M as a median point and further includes the brightest tone value B as one end of the range; a black edge statistics unit that measures frequency distribution of tone values of black edge inside the quadrangular or polygonal area and measures a greatest brightness value b in a black edge range, which is a range of tone values in which the black edge is distributed significantly.
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