Research On An Improved Pencil Drawing Algorithm

With the rapid development of computer technology,non-photorealistic rendering(NPR)gradually into the horizon of people which is corresponds with photorealistic rendering,NPR refers to make use of computer to make pattern generation with a certain style of art created by human technology.NPR is a combination of computer science and human artistic creation,it has been the focus of research in computer graphics in recent years.It provides a wealth of imagination to people and computing platform to create art.Non-photorealistic rendering technology is developing rapidly,a wide range of applications,in-game animation,advertising media,virtual reality,video production,computer-aided design and other fields to obtain in-depth research and extensive applications.Using non-photorealistic rendering techniques can generate pencil drawing,ink drawing,paint drawing,pen drawing etc.such different artistic styles of painting.The article chooses pencil drawing as the main object of study,to carry out simulation innovative rendering algorithm.Pencil drawing generation can be roughly divided into two parts:the first part,the stroke contour map is formed;the second part,the texture tone image is formed.This paper makes innovation and improvement in the tone forming part of the texture map.There are three innovations:First,collect a lot of pencil drawing and classify them into different categories,such as landscape drawings,architectural drawings,characters,after dividing each category into different categories,respectively,make the pencil histogram statistics to different categories,and fitting for the class histogram curve.The histogram curve is correspond with the input image and match the categories,so as to achieve the purpose of classification drawing.Second,put the random noise figure to be the base which has the same size as the input image and multiplied by the number of iterations tone image fitting,using the optimization algorithm calculate the number of iterations of the multiplication.Finally,according to the iteration of random noise map to obtained the noise map,and tone image guide the noise pattern generation.Third,Divide the image into different gray scale areas,make use of LIC to form the single texture map with different lengths and different direction which is also fit for current area.Combined the single texture map with corresponding segmentation diagram in region,and then it will have a pencil renderings with different texture directions.