| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that the pseudo increase in gradation by using both error diffusion processing and dither processing is difficult, when the distance between gradations which a display device can display is not equal. SOLUTION: This apparatus has a bit number extending means 100 for increasing the number of bits of image signals byΔb, where at least a formula Log2(n×m)≤Δb is satisfied, for the bit number b of an image signal to be inputted into a display device 103; a gradation limit table for limiting an image signal to a gradation of (n×m) times a gradation c while presuming that the number of gradations is increased simulatively to about (n×m)-fold by the dither processing; a gradation limit means 101 for performing the error diffusion processing using the limited differential as a displayed error; and a level converting means 104 for applying the dither processing to the image signal by using a dither constituent depending on the image signal, and finally converting the signal into a signal of b-bit and c-gradation. COPYRIGHT: (C)2004,JPO
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