JPS57184369A - Picture converting device - Google Patents

Abstract

PURPOSE:To eliminate the noise and to improve the picture quality, by performing a filtering operation to eliminate the high band component of a binary picture, converting the binary picture into a picture having the gradation corresponding to the output picture element and delivering the converted picture after binary coding it by the dithering. CONSTITUTION:The input binary picture signals of a memory device 10 are successively shifted to a shift register 2 synchronizing with the clock given from a clock generator 1. It is uspposed that an original picture comprises (NXM) units of picture elements in all, and the total 8 bits of the register 2 are connected to the address input of an ROM3. For the ROM3, the weighting mean value of each bit of an address signal is written into an address that is designated by the address input. Thus the said mean value is delivered from the ROM3 with application of the address input, and this output is fed to a comparator 4. The output of the comparator 4 is turned into a binary signal that is set at ''1'' and ''0'' when the increment of the mean value given from a generator 5 is large and small respectively. The generator 5 functions as an ROM forming a dither pattern generator.