面向二维工程CAD图的拓扑完整性校验算法  

Topology Integrity Verification for 2D Engineering CAD Drawings

作　　者：周浪[1] 苏智勇[2] 唐卫清[3] Zhou Lang;Su Zhiyong;Tang Weiqing(College of Information Engineering, Nanjing University of Finance & Economics, Nanjing 210023;School of Automation, Nanjing University of Science & Technology, Nanjing 210094;Institute of Computing Technology, Chinese Academy of Sciences, Beijing 100190)

机构地区：[1]南京财经大学信息工程学院,南京210023 [2]南京理工大学自动化学院,南京210094 [3]中国科学院计算技术研究所,北京100190

出　　处：《计算机辅助设计与图形学学报》2017年第5期895-905,共11页Journal of Computer-Aided Design & Computer Graphics

基　　金：国家自然科学基金(61300160)

摘　　要：拓扑信息是工程CAD图的核心,其完整性直接影响着工程设计的效率和质量.针对二维异构工程CAD图的拓扑完整性认证问题,提出一种基于半脆弱数字水印技术的通用拓扑校验算法.首先根据对象间的连接关系构造拓扑图,并对各对象进行统一编码,实现异构图纸拓扑关系的统一描述;然后根据拓扑图建立对应的拉普拉斯矩阵,利用拉普拉斯谱计算各对象的拓扑特征值;最后将拓扑特征值嵌入到各对象的几何不变量中.该算法通过比较提取的特征值序列与对象当前的拓扑特征值来验证其拓扑完整性.理论分析和实验结果表明,文中算法对于全局和局部相似性变换、拷贝、镜像和文件格式转换等非恶意操作具有较强的鲁棒性,同时对于各种恶意拓扑攻击具有精确的定位能力,可以广泛应用于各种工程CAD领域.Topology information plays the most important role in engineering CAD drawings.The efficiency and quality of engineering design often depend on the topology integrity of drawings.This paper proposes a general topology authentication algorithm,which is inspired by the semi-fragile watermarking scheme,to verify the topology integrity of heterogeneous engineering CAD drawings.Topology graph is firstly built according to the topology relation among objects with uniform codes.Then,the Laplacian matrix is constructed and its Laplacian spectrum is computed to generate topology feature values.These values are then embedded into the geometric invariants of objects.Topology integrity verification is achieved through comparing the extracted binary values with the topology feature values computed according to the current topology relation.Theoretical analysis and experiments have demonstrated that the proposed scheme can not only detect and locate malicious topological modifications,but also yield strong robustness against various topology-preserving modifications,such as global and local similarity transformations,copying,mirroring and file format converting.It's believed that the proposed scheme is a general algorithm and applicable to various kinds of heterogeneous engineering CAD drawings in industry practices.

关 键 词：工程CAD图 拓扑认证 拓扑完整性 拉普拉斯矩阵 数字水印 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]