An Adaptive Halftone Algorithm Based On HVS And Printer Model

Digital halftone is a screen technology. It bases on human visual system and image characteristics, using mathematical tools and computer tools in binary or polychromatic binary device to realizes image representation. Now, it plays a significant role in printing ,display fields. With improving performance of digital hard-copy device, halftone algorithm has become one of the key factors that affect the quality of the output.In this thesis, efficient and high quality digital halftone method for high quality digital hard-copy output requiremnt is studied. First, due to the poor contrast and edge transition discontinuity existing in the standard error diffusion and the edge enhancement error diffusion, this paper presents an adaptive halftone algorithm based on HVS(human visual system) and printer model. The visual difference between the printed image simulated by the printer model and the original image is feedbacked to compensate the original image. This enhances the contrast of the image. Also the Sierra filter is used to solve the problem of the gray transition discontinuities caused by the Floyd_Stein filters. Second,the simulation and compare for the adaptive halftone algorithm based on HVS and printer model. The results show that the algorithm can effectively improve the image quality and image contrast, reduce the dot gain phenomenon and obtain smooth transition edge. Finally, the objective evaluation methods are used for the evaluation of simulation graphs. The results showed that: the proposed algorithm is better than the standard error diffusion algorithm and edge enhancement error diffusion algorithm in the statistical properties of overall errors and structural similarity , and halftone images obtained have good visual effects.