4-Row Serpentine Tone Dependent Fast Error Diffusion

Yafei Mao, Lluis Abello, Utpal Sarkar, Robert Ulichney, Jan P. Allebach

Abstract: Error diffusion is a popular technique widely used in desktop printers, especially inkjet printers. However, since the conventional error diffusion is computed in raster order, it produces worm artifacts in the highlights and shadows. In addition, as a serial algorithm, it limits the efficiency and flexibility of hardware implementations. To address these two issues, we propose a novel serpentine based error diffusion algorithm that uses tone dependent error weights and thresholds. We also propose an expanded error weight location matrix to improve the halftone quality in the extreme tones. With this new algorithm, we achieve better halftones comparing to the original tone dependent fast error diffusion, especially in the quarter tones.