| 摘要 |
PURPOSE:To secure the desired gradation frequency of input multilevel image data and to prevent the degradation of image quality from being generated in a reproducing image even when the variable magnification of an image is executed, by providing a threshold matrix generating means, a dividing means to divide the input image data into the blocks of a prescribed size and a binalization means. CONSTITUTION:The titled device provides threshold matrix generating means 901 and 902 to generate the threshold matrix of a size to correspond to the desired gradation frequency, dividing means 904 and 905 to divide the input image data into the blocks of the prescribed size based on a resolution ratio between the input image data and an output image data and a variable magnification ratio between the input image data and the output image data and a binalization means 908 to compare the threshold of the image data in the divided block and the threshold of the threshold matrix and to execute binalization. Thus, while the desired gradation frequency is secured, without generating the degradation of the image quality, enlargement, reduction and the variable magnification can be executed. |
