基于改进几何哈希法的矢量图形检索

Vector Graphic Retrieval Based on Modified Geometric Hashing

针对图形文件以矢量方式记录几何实体的特点,提出了一种基于改进几何哈希法的图形检索算法。与图像的对应处理方式相比,该算法充分利用图形的矢量信息,以实体基准点和实体的准确几何形式描述几何实体;在检索过程中,每个图形实体仅有基准点参与排序和查询,哈希表数据组织形式简单,查询速度快;通过验证图形实体属性,保证了查询结果的准确性。最后以矢量图形文件为图例,验证了方法的有效性。

In view of the fact that geometric entities are recorded in vector form in graphics file, this paper presents an algorithm based on modified geometric hashing for shape retrieval. Compare with relevant process for images, the algorithm describes geometric entities by accurate vector information such as datum mark and entity properties. For each entity, only datum mark was involved in sorting and retrieving process, which makes the organization for hash table simply and the retrieval speed quickly. The accuracy is assured by verifying the property of geometric entities at last stage of retrieval. The experiment shows that the algorithm is effective.