| 摘要 |
PURPOSE: To provide an improve half tone screen, in which continuous images are screen-processed using frequency modulation screening technique, and a processing method for the same by executing the processing order of non- processed picture elements inside continuous tone images at random according to the two-dimensional curve of spatial filling-up. CONSTITUTION: A counter 8 is counted up for every clock pulse, a new coordinate value [i, (n)] is outputted from a block part 10 and since that coordinate value is used as an address value to a pixel memory 20, the same tone pixel value P is provided. This pixel value is added with an error value E [i(n-1), j(n-1)] preserved in a register 60 after preceding half tone processing, and that sum is compared with a threshold value 41 by a block part 40. Continuously, a new error value E [i(n), j(n)] is simultaneously calculated from the difference between the pixel value P and a compare value H and preserved in the delay register 60. |
