| 摘要 |
PURPOSE:To attain a linear density conversion processing to a dither picture with the gradation characteristic of an original picture maintained with respect to an optional variable power ratio and to prevent the occurrence of moire by obtaining the density data of a converting picture element from the peripheral reference picture element from the peripheral reference picture element of a sample picture element and dither processing this data again. CONSTITUTION:A sample picture element selection part 4 obtains the converting picture Q, a position (X, Y) on the original picture of (I, J) based on the previously applied variable power ratio Cv and a reference picture element selection part 5 selects an original picture element group including the reference picture element Of(i, j) as the reference picture element. Then, density arithmetic part 6 calculates average density in a reference area from the density information {Do(i, j)} (0<=i<=3, 0<=j<=3) of the reference picture element {O(i, j)} (0<=i<=3, 0<=j<=3) of the selected (4X4) and makes the value the density data Dq(I, J) of the converting picture Q(I, J). Further, the density data Dq(I, J) of the converting picture Q(I, J) is dither processed and binarized by using the second dither pattern in a dither processing part 7. |
