Verfahren zur Grauwertkorrektur für binäre Bilddaten

摘要

A method of gray value correction for binary image data, preferably screened image data, with a local gray value by a desired correction magnitude includes filtering the image data quantized with n bits with an asymmetrical low-pass filter whose filter window is smaller than a screen cell. By a threshold value operation, corrected binary image data is obtained from the filtered image data. Optimum threshold values are selected from a threshold value table as a function of the local gray value and of the desired correction magnitude.