Subjective image quality for multi-level error diffusion and its objectiveevaluation method

The quality of images produced by multi-level error diffusion was evaluated both subjectively and objectively. The images were recorded on color trans parencies by a digital film recorder with a resolution of 1600 dpi. Thirty- six sample images with four different resolutions and nine different quanti zation levels were prepared, and the tone reproduction, color reproduction, graininess and sharpness of the images were analyzed and evaluated. We fou nd that the graininess gives the strongest influence on the quality of the image. The relationship between observer rating values and measured quality criteria are also discussed.