| 摘要 |
PURPOSE:To improve both the image resolution and the gradation showing capacity by calculating the value showing the degree of continuity of gradations of input picture signals, controlling the amplitude of threshold value with the calculated value and converting the input picture signal into a pseudo half tone by said threshold value. CONSTITUTION:For the digitized picture data obtained from a picture input device 11, the contrast of a noticed picture element is calculated by a contrast calculating circuit 12. A threshold value deciding circuit 14 changes a dot converting threshold value that is previously decided based on the calculated contrast value and then delivers it to a binary coding circuit 15. The circuit 15 compares the picture signal obtained from the device 11 with the changed dot converting threshod value. Then a binary picture signal is delivered. |
