Patent ID: 7440142
Filing Date: 2008-10-21
Classification: H04N

Abstract:
1. An image processing system having an output image calculating means which receives an input gradient number m, input image data I(x,y) whose input gradient number is m, and an output gradient number n and calculates output image data O(x,y) having an output gradient number of n on the basis of the following formula (1), wherein α=(n−1)/(m−1)*I(x,y), gmax represents the maximum value of the dither matrix, d(xd,yd) represents the value of the dither matrix (0≦d(xd,yd)≦gmax), xd=x mod dsize_x, yd=y mod dsize_y, dsize_x represents the size of the dither matrix in x direction, and dsize_y represents the size of the dither matrix in y direction, wherein the improvement comprises correction determining means which calculates α in the formula (1) on the basis of the input gradient number m, input image data I(x,y), and the output gradient number n and determines whether the calculated α is an integer, a correction means which makes a correction to make the calculated α not an integer to calculate α′ when the correction determining means determines that the calculated α is an integer, and an operation control means which controls the output image calculating means to calculate the output image data O(x,y) on the basis of a formula obtained by substituting the calculated α′ for α in the above formula (1) when the correction determining means determines that the calculated α is an integer, whereas to calculate the output image data O(x,y) on the basis of the above formula (1) when the correction determining means determines that the calculated α is not an integer.