| 摘要 |
PROBLEM TO BE SOLVED: To provide an image processing apparatus having a high gradation characteristic and an accurate density characteristic even when the number of gradation values of an output value for image reproduction generated by the halftone processing by means of the AAM method is small. SOLUTION: A halftone processing unit references a dither matrix configured correspondingly to pixels of a plurality of cells for each cell comprising the fixed number of pixels to convert the input gradation value of pixels of an input image into an output gradation value whereby dots are formed in each cell. The halftone processing performs the conversion by referencing the dither matrix in a way that a pixel at a gravity position in each cell is associated with the dot center pixel of the dither matrix. Then the dither matrix has a plurality of gamma tables correspondingly to each pixel of the plurality of cells, and gamma tables with different discrete output gradation values with respect to the input gradation value are allocated in a distributed manner in the same index pixel group located on a prescribed displacement vector with respect to the dot center pixel in each cell. COPYRIGHT: (C)2007,JPO&INPIT
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