An Edge Enhanced Technique for Digital Halftoning Using Error Diffusion

Halftone image is a binary image that preserves the visual quality from the original continuous-tone image, and is used everywhere for printing and output documents. In this paper, a modified error-diffusion halftoning scheme is proposed that the error is diffused dynamically according to the magnitude of gradient and the proposed impact functions. From this adjustment, the proposed scheme can enhance the edges and preserve the smooth regions. The experiments demonstrate the performance of the proposed scheme with different settings of the impact functions. Also from the testing procedures, the settings of the impact function can automatic obtained from the distribution of gradient.