Edge preserving multiscale error diffusion algorithm for green noise digital halftoning

Multiscale error diffusion (MED) is superior to conventional error diffusion algorithm as it can eliminate directional hysteresis completely and possesses good blue noise characteristics. However, due to its filter design, it is not suitable for printing processes which suffer instable dot generation and large dot gain. This paper presents a feature preserving multiscale error diffusion algorithm for green noise digital halftoning. To cope with the edge of the image, the selected diffusion filter is modified according to the edge orientation. Spatial statistics analysis and simulation results show that the proposed algorithm does not only provide outputs of green noise characteristics, but preserve edge details and eliminate pattern artifacts and directional artifacts as well.