摘要
以几何图元为基本元素,提取特征并采用分层结构进行工程图检索.首先对矢量图形进行预处理,然后对不同图元分别提取图元统计特征和结构特征用以描述其几何信息.采用分层检索结构用以提高检索效率:第一次检索利用直线段数量、圆弧数量等比较简单的统计特征对待检索的工程图数据库进行匹配,以缩小检索范围;以第一层检索得到的结果为候选集合,根据直线斜率、圆弧度等进行二次检索.和已有一些典型的工程图检索算法相比较,这篇文章的算法把提取的统计特征和结构特征采用分层结构进行组织,用以避免两种不同类型的特征采用单一向量描述存在的难以归一化问题.实验结果表明,该算法在检索准确率和检索效率方面都有一定程度的提高.
This paper presents an algorithm that it can extract features from basic geometry element graphics and retrieve graphics based on multi-stage architecture. At first, the algorithm preprocesses the vector graphics. Then the graphics statistic features and structure features can be extracted from different graphic elements respectively. Those features help to describe information of graphics. The multi-stage architecture is used in this algorithm to improve efficiency of retrieval. In first retrieval, the simple statistic features, such as amount of lines or arcs, are used to match the graphics in the database in order to reduce the retrieval scope. In second retrieval, some features such as slope of line and radian of arc are used to retrieve graphics based on the results from the first retrieval. Comparing with some classic retrieval algorithms used in engineering graphics, statistic features and structure features which are extracted based on this algorithm are organized under the multi-stage architecture. The method avoids the difficult problem of normalization, in which two different types of features are described in the single vector. The experiment reshlts indicate that this algorithm has improved accuracy and efficiency in graphic retrieval.
出处
《浙江工业大学学报》
CAS
2008年第5期499-503,508,共6页
Journal of Zhejiang University of Technology
关键词
矢量图元
特征提取
分层检索
检索性能
retrieval
feature extraction
multi-stage retrieval
retrieval performance
