| 摘要 |
PURPOSE:To obtain a good half tone recording having little fluctuation in picture quality over the ranges from a low density to a high density by attaching the regularity of stripe shape or of matrix shape on a binarization threshold in the arranging direction of a picture element and changing it. CONSTITUTION:A picture signal generating part 3 outputs a picture density signal 4 corresponding to an address signal 2, and compares its size of level with that of the minimum density level signal 8 possible to print at a comparator 5 and the discrimination signal 6 is inputted to a switching means 9. When the picture density signal 4 is larger than the minimum density level signal 8, the picture density signal becomes a print signal 10 as it is. Next, when the picture density signal 4 is smaller than the minimum density level signal 8, a binary recording is performed electing either the minimum level signal or a white density level signal. A method to express a gradation is as follows: the error of density generated in the binarization is stored at a memory 11, and a correcting density signal is generated by adding the error at the periphery of the picture element is process on the picture density signal in proccess to read out from the memory, and the correcting density signal is subjected to binarization processing, generating a print density signal, and the difference between the correcting density and the print density is recognized as the error of the picture element in process. |
