Non-photorealistic Image Rendering In A Number Of Algorithms

Since mid 1990s, Non-Photorealistic Rending has gradually become one of the most active research topics in the present fields of computer graphics. The paper researches algorithms about halftone, stipple simulation, paint simulation and pen-and-ink simulation which are in the area of Non-Photorealistic Rending.In this paper, error diffusion algorithm is studied. Frequency analysis method is presented to show up the reason for the artifacts caused by error diffusion algorithm. Six improved algorithms are studied and implemented, and experimental results are contrasted. Combining pyramid decomposing method and greedy algorithm, we bring up an improved error diffusion algorithm which can effectively eliminate artifacts. Rejection algorithm and point relaxing algorithm which are in the area of stipple are studied and the experimental results are given. We design and implement a stroke-based multi-scale algorithm which creates several scale-distinct reference images by pyramid decomposing. We also study and implement a stroke-based pen-and-ink simulation algorithm which can generate and clip strokes.