New edge-enhanced error diffusion algorithm based on the error sum criterion

A new edge-enhanced error diffusion algorithm, based on Eschbach's algorithm, is proposed. Thick-edged artifacts as well as small edge-enhancement effects for the bright or dark pixel values are observed in the previous algorithm. By analyzing the phenomena, a new improved algorithm is proposed by using the diffused error sum and input pixel value. An input pixel is classified into a normalor edge-region pixel based on the error sum criterion. A new error calculation is then employed for the edge-region pixel, while conventional error calculation is used for the normal-region pixel. The proposed method requires only a few additional calculations and provides edge-enhanced binary output images. The edges are in fluenced less by the brightness offset, and thick-edged artifacts are reduced.