A Stylized Colored Pencil Drawing Filter

Pencil drawing is a popular form of painting art, and colored pencil drawing is a specialbranch of this art style. Colored pencil drawing is getting more and more appreciation. Its soft,rough, slightly fuzzy texture gives people a kind of elegant appeal, and its line style is able todepict objects expressively.Generating all kinds of painting styles from natural images is an important research directionin the field of non-photorealistic rendering (NPR). But so far, the existing methods insimulating the real colored pencil drawing effect are not very successful. The reason is thatthe direction information of texture is not suitable for color pencil drawing effect of smallparticles, and color mixing principles have not been established reasonably.This paper investigates the key problems for generating colored pencil drawings. The realcolored pencil pictures employ a limited set of colors to show many different colors throughoptical mixture. To simulate this mixing process, we propose a method which mainly includestwo parts: the first part is color quantization which uses a collection of primary colors toquantify the continuous color on the original image; the second part is color mixing whichcombines the primary colors optically to show a much varieties of colors. Using this colormixing method based on fixed primary colors, combining uniform texture with no directioninformation, our method can show the effect of fine particles for the color pencil.We further completed the combination of mixed colors and textures to produce a coloredpencil drawing texture. After synthetizing this texture with lines effect which has thecharacteristics of hand drawing, our method ultimately generates expressive color pencildrawing effect.