| 摘要 |
PURPOSE:To reproduce both halftones and thin lines by performing the dither processing of a video signal by a dither processing circuit, by emphasizing the contour of the video signal, and by giving the output of an emphasizing circuit priority to the output of the dither processing circuit. CONSTITUTION:For four mutually adjacent picture elements, comparators 10-13 for quad encoding are given threshold levels from density 1 to density 4 to obtain five gradations. Outputs of those comparators are transmitted to the following stages via latch circuits 24-28. The signal passed through latch circuit 28 is delayed by one picture element each in shift registers 31 and 32 and black-emphasized signal (p) and white-emphasized signal (q) are obtained through inclusive OR gates 33 and 34, AND gates 35-38 and 43, and OR gate 40. Then, OR gate 42 and AND gate 43 output the emphasized signals with priority to a dither output. |
