JPS5466041A - Graphic quantizing device - Google Patents

Abstract

PURPOSE: To obtain a graphic quantization signal which corresponds to the density at each part of a pattern, by controlling the threshold level of the pattern quantization signal corresponding to the density of the pattern in a scan block.

CONSTITUTION: Paper surface 10 with a pattern drawn is scanned by scanner 21 of scanning part 20, and a photoelectrically-converted photo-detection signal is quantitized by quantizing circuit 22 to which a threshold level equivalent to the white level of the paper surface has been set. As a result, circuit 22 generates a quantization signal equivalent to pattern density inside the area between the change point from a white level into an ink block, and the next change point. This quantization signal is detected by black-level detection circuit 42 of optimum-threshold- level setting part 40, and then applied to threshold-level decision circuit 48, which is gated for a block interval and has a prescrived staircase-shaped threshold level set, via counting circuit 41, shift register 44, shift register 45, counting circuit 46, and coincidence circuit 47, so that the optimum threshold level equivalant to the pattern density of each block of circuit 48 will be applied to comparator circuit 49. Consequently, the quantization signal is formed which corresponds to the density of the pattern formed at parts different in density.

COPYRIGHT: (C)1979,JPO&Japio