| 摘要 |
The improved image processing apparatus has a circuit for tonal and color matrix transformations of image which performs tonal transformation on image data of three primary colors and with which a 4x3 matrix is multiplied by a column matrix composed of the tone transformed image data so as to produce four-color image data including image data of a block color, and this circuit for tonal and color matrix transformations of image has: a lookup table in which the values of multiplication of the tone transformed image data, which have been obtained from the image data of three primary colors using nonlinear tonal transformation curves for the respective colors, by the elements of the matrix to be subjected to matrix multiplication have been written for each color in association with all of the image data of three primary colors; address signal generator which generates address signals for referencing the lookup table from the image data of three primary colors and color identification signals; and accumulator which adds the values of multiplication within the lookup table for each color as addressed by the address signal generated by the address signal generator and which repeats the addition by a predetermined number of times. The apparatus features a smaller circuit scale and is capable of precise corrections of four colors Y, M, C and K by performing independent nonlinear transformations on the respective colors.
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