High Quality Multi-level Error Diffusion Method Employing Variable Threshold

We propose a new multi-level error diffusion method employing the variable threshold, which realizes half toning with high quality. In the proposed method, dissimilar textures around quantization levels, which are the cause of the low image quality and obtained by a conventional method, are decreased by using the variable threshold. In this paper, we apply the proposed method to various standard digital images. And the simulation results show that the method is superior to other multi-level error diffusion methods.