Abstract

Different types of binarization procedure exist which can be used to convert a graytone image into a halftone picture. Dither methods are based on sequential pointwise decisions between the original distribution and the binary result. Furthermore, digital processing allows active and integrative concepts. Error diffusion techniques are sequential realizations which incorporate local processing. We discuss halftoning by global processing. Our scheme is based on an iterative Fourier transform algorithm with control of constraints in the image as well as its spectrum. We will show how the image on one hand and the texture formed by quantization noise on the other hand can be influenced and shaped. Variation of the basic constraints is discussed and experimental results shown.

© 1988 Optical Society of America