Vectorization of line drawing image based on junction analysis

作     者：CHEN JiaZhou LEI Qi MIAO YongWei PENG QunSheng 

作者机构：College of Computer Science Zhejiang University of Technology State Key Laboratory of CAD&CG Zhejiang University 

出 版 物：《Science China(Information Sciences)》 (中国科学:信息科学(英文版))

年 卷 期：2015年第58卷第7期

页      面：99-112页

核心收录：

学科分类：0810[工学-信息与通信工程] 0808[工学-电气工程] 08[工学] 080203[工学-机械设计及理论] 0802[工学-机械工程] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：supported by National Natural Science Foundation of China(Grant Nos.61303138,61272309) Open Project of the State Key Lab of CAD&CG,Zhejiang University(Grant No.A1428) 

主　　题：vectorization line drawing line tracking junction analysis vector graph 

摘      要：Converting a scanned or shot line drawing image into a vector graph can facilitate further edit and reuse, making it a hot research topic in computer animation and image processing. Besides avoiding noise influence, its main challenge is to preserve the topological structures of the original line drawings, such as line junctions, in the procedure of obtaining a smooth vector graph from a rough line drawing. In this paper, we propose a vectorization method of line drawings based on junction analysis, which retains the original structure unlike done by existing methods. We first combine central line tracking and contour tracking, which allows us to detect the encounter of line junctions when tracing a single path. Then, a junction analysis approach based on intensity polar mapping is proposed to compute the number and orientations of junction branches.Finally, we make use of bending degrees of contour paths to compute the smoothness between adjacent branches,which allows us to obtain the topological structures corresponding to the respective ones in the input image.We also introduce a correction mechanism for line tracking based on a quadratic surface fitting, which avoids accumulating errors of traditional line tracking and improves the robustness for vectorizing rough line drawings.We demonstrate the validity of our method through comparisons with existing methods, and a large amount of experiments on both professional and amateurish line drawing images.