| 摘要 |
PURPOSE:To perform the binarization processing corresponding to image regions such as a photograph region, a character region or a dot region by judging the type of image data on the basis of a comparing result, by providing a calculation means for calculating average density at a pixel block unit, a means for calculating the average density difference between a pixel block and the adjacent pixel block and a comparing means for comparing the average density and average density difference with predetermined values. CONSTITUTION:An image signal 4 corrected in gradation is inputted to a fixed threshold value circuit 5, a dither circuit 6 and a moire suppressing circuit 7 to be binarized. The image signal 4 is also sent to density difference detection circuits 9, 10. The density difference detection circuit 9 detects the density difference between pixel blocks and the density difference detection circuit 10 operates the density differences between each pixel in the block and several pixels adjacent thereto. When the outputs of the density difference detection circuit 9, 10 are respectively set to 19 and 20, these two signals 19, 20 are inputted to a judge circuit 11 and the selection signal 13 corresponding to the type of the image signal 4 is outputted from the judge circuit 11 to change over a selector 8 and the binarized data 21 suitable for the type of each image signal is sent to a printing part 12 to reproduce an image. |
