Inverse Halftoning Scheme of Error Diffused Images Based on the Neighboring Halftoned Pixel Patterns

Abstract

In order to evaluate halftoned images or halftoning techniques, inverse halftoning schemes of error diffused images have been studied. Most of the conventional methods are either simple filtering, which is not satisfactory, or complicated edge direction detection, which can be too complicated to design. Here we propose a method that is based on neighboring halftoned pixel pattern conditioning. It was found that the improvement of SNR of restored halftone image obtained by the proposed method, compared to the conventional 5x5 Gaussian method, is from 2 to 4dB as great.