Algorithm For Automatic Orientation Of Computer Paper Cut-out

Non-Photorealistic Rendering (NPR) is a newly developed research area in computer graphics and,in some fields,NPR is more individually and more artistically than photorealistic rendering. Thus, it has a wide range of applications in the fields ranging form education, entertainment to art.Paper cut-out is one of the traditional folk arts in China. The tools and the materials it used are very simply,and it can be used in very abroad fields,many people take it as an important part in their life. The art of paper cut-out portray the images through various line and contrast. Base on this peculiarity of paper cut-out,this thesis simulates the pattern of paper cut-out,and recur the art form in the computer. The thesis aims to study the theory of how to fix decorative pattern on proper spot automatically based on medial axis from computation geometry.According to the function and characteristic,paper cut-out is sorted into four classes:(1) Basic structure pattern. We use the basic structure patterns to figure the physique structure of the objects,such as lines,circularities,arcs and various curves. (2) Character pattern. We take the character pattern to express the character of the objects that it wants to represent. (3) Special pattern. We use the special pattern to express the facial features on the animal's head. (4) Decorative pattern. At the end, we get a pattern gallery for these paper cut-out patterns, and apply the patterns to generate paper cut-out.And then, base on the character of the paper cut-out pattern,we obtain the area of the pattern, including polygon area and circle area. To ensure the patterns are connected to the paper-base, we disconnect the sideline when they are rendering.This thesis computes medial axis of paper-cut's contour and inserted point of decorative pattern by medial axis algorithm,and then fixes decorative pattern on proper spot automatically according to the type, position, direction and size of the patterns. To prevent the intersection of the patterns, we give a judgment when they are rendering.Compared to handmade paper-cut,computer assisted generation of paper cut-out images by using NPR can make it more easier when you want to change some patterns of paper cut-out image,and can fix on patterns automatically by using medial axis algorithm and improve automation degree. Computer paper cut-out can be widely used in the area of vignette design,electric cart, advertisement,games and cartons.Sum up,the main contributions of this thesis are as follows:...