Method and circuit for contrast enhancement

Abstract

Abstract A method and an apparatus are provided for contrast intensification in the reproduction of masters in the field of electronic image processing by engraving devices and scanners. In the image-point-wise, opto-electronic master scanning, two outer field signals are obtained in addition to the image signal by scanning a first outer field and a larger, second outer field. A first differential signal and a second differential signal are generated from the image signal and the outer field signals and a third differential signal is generated from the two outer field signals. The first differential signal is combined with at least one of the other two differential signals to form an auxiliary signal which is added to the first differential signal in order to obtain a correction signal. The correction signal is then superimposed on the image signal for the purpose of contrast intensification. By employing a second outer field signal, it is particularly the disturbing edges around hard master contours which are avoided.

Inventors

• 👤 Uwe Gast

Bibliographic Details