Display method for intermediate tone

Abstract

Abstract PURPOSE: To constitute the intermediate tone pattern including the character picture as high quality picture, by calculating the gradient of concentration with the concentration of the picture elements adjacent each other, and performing intermediate tone display through the selection of the threshold matrix having smooth boundary when this gradient is of high contrast. CONSTITUTION: After the video signal VD is fed to the normalizer 30 to perform normalization and it is stored to the N line buffer 31 tentatively, the output of the buffer 31 is sequentially added to the concentration gradient discrimination operation unit 32, and the operation unit 32 performs processing to select the optimum threshold matrix T. In this processing, various patterns suited to the concentration gradient depending on direction are memorized in the threshold level set memory 37, the address controller 35 is started with the control of the system controller 38, the address converter 36 is controlled according to the matrix T selected from the operation unit 32, the matrix T is read out from the memory 37, it is compared with the video concentration normalized with the comparator 33, and the result of comparison is outputted. COPYRIGHT: (C)1979,JPO&Japio

Inventors

• 👤 Koichi Ejiri
• 👤 Keiji Sekikawa

Bibliographic Details