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Proceedings Paper

Adaptive halftoning based on iterative convolutions
Author(s): Thomas Zeggel; Olof Bryngdahl
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Paper Abstract

An iterative halftoning method with a space-variant, input-dependent control of the binarization noise is presented. The algorithm is based on experiences with the iterative Fourier transform algorithm. It uses a convolution with an appropriately chosen finite impulse response (FIR) filter and a spatial operation instead of the Fourier transform and spectral operation. An adaptation of the spectral properties to the local grayvalue of the input image is demonstrated. Besides the local grayvalue the local image gradient is considered. Incorporation of the information about the direction of the local gradient is possible by using a non-symmetric impulse response. The idea is to preserve the spatial frequency content of the image along the gradient at the expense of the content perpendicular to it. The control of the various free parameters of this halftoning method is discussed. Experiments with a gradient- adaptive, space-variant impulse response according to a local transfer function covering elliptic areas show an improved reproduction of high frequencies in the binary image.

Paper Details

Date Published: 22 April 1996
PDF: 8 pages
Proc. SPIE 2657, Human Vision and Electronic Imaging, (22 April 1996); doi: 10.1117/12.238743
Show Author Affiliations
Thomas Zeggel, Univ. Essen (Germany)
Olof Bryngdahl, Univ. Essen (Germany)

Published in SPIE Proceedings Vol. 2657:
Human Vision and Electronic Imaging
Bernice E. Rogowitz; Jan P. Allebach, Editor(s)

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