Iterative error diffusion halftoning using a zero phase error filter

The halftone quality of an error diffusion halftone depends on the error filter response. Apart form the magnitude response being a low pass, it is desirable to have a zero phase response. We propose the iterative error diffusion halftoning algorithm that allows use of non-causal error filter (such as zero phase error filter). We present simulation results showing that the proposed halftoning scheme is substantially better, specially in retaining the sharpness of the edges and in truthfullness