Improved Edge Enhanced Error Diffusion Based on First-Order Gradient Shaping Filter

Abstract

The reconstruction of edge information using the prevailing error diffusion halftoning is represented as weak in visual and objective measuring criteria. In the previous work, an excellent improvement in reconstructing edge information of original image into belevel-toned image was achieved by adding an edge enhancing filter to the original error diffusion method. In spite of such effectiveness, the edge enhancing method made degradation in general information representing average tone of original image and even in edge information when excessive edge enhancing parameter is applied. In this paper, we seek a novel edge enhanced error diffusion method to preprocess original image so that further enhance edge information while preserving the good characteristic of the original error diffusion in general information. To confirm the achievement of the proposed method, we compare the method with both the standard error diffusion and the conventional edge enhanced error diffusion for Lena image in various objective measuring criteria.