Edge-Directed Error Diffusion Halftoning

In this letter, we propose two simple extensions of the existing error diffusion (ED) halftoning technique: one stops the diffusion at edge pixels, and the other tunes the support of the diffusion kernel to match the local edge orientation. Experimental results are used to show that the proposed edge-directed ED schemes achieve noticeably better performance over existing ED with edge enhancement for a certain class of gray-scale images.