| 摘要 |
PURPOSE:To adjust minutely the gradation of a reproduced picture, by adding/ subtracting a prescribed density to/form a basic density profile of a dither matrix pattern for forming a binary picture signal. CONSTITUTION:A CCD 1 reads a original picture, which is A/D-converted 2, a digitized picture signal reading signal is compared 3 with a threshold train mentioned hereunder, for binary-coding it, its output is applied to a printer 4 and reproduced. On the other hand, a dither matrix pattern data of the basic profile is read out and applied to an adder 6 from an ROM 7 storing the dither matrix pattern and a prescribed density set to a density adjusting switch 5 is added and the threshold train of the dither matrix pattern having a profile of the form shifting the average density of the basic profile is obtained and the result is given to the comparator 3. Thus, the suitable density comparison is attained by using the dither matrix pattern of a single kind in response to a remarkable change in the average density of the original picture. |
