Sharpness emphasis method in image scanning recorder

Abstract

Abstract PURPOSE: To obtain sufficient sharpness emphasis effect without emphasizing original image graininess, by discriminating the change amount of unsharp signals to control the amount of sharpness emphasis signal. CONSTITUTION: An unsharp signal used is obtained by scanning an original image through auxiliary scanning window 2 having a scanning area 4W5 times as large as that of main scanning window 1. Since the scanning area for this unsharp signal is larger than that through window 1, the effect of original is averaged and causes little changes in the signal when flat areas free of original details are scanned. On the contrary, since the unsharp signal changes in the case of scanning the areas with original details present, this change amount is detected, and when this is small, graininess is improved by reducing a gain in a masking circuit or peaking circuit, or elevating a slice level with slice level setting circuit 9 to render sharpness emphasis effect weak or to zero. When the change amount is large, the sharpness is able to be emphasized by stopping these controls. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Hitomi Ahei
• 👤 Masurou Kunisawa
• 👤 Atsuo Hirata
• 👤 Yasumasa Araki

Bibliographic Details