Abstract: The basic ray-based method is time consuming and only uses the information of triangle facets. An extended ray-based method was proposed based on the principle of non-intersecting pencil of planes. The key points of this method were as follows: firstly, a group of rays was scattered evenly from the center of the 3D model to intersect with triangle facets, and the non-intersecting pencil of planes determined by the rays was used to get the intersection points; secondly, the retrieval model was established to improve the 3D model retrieval effectiveness, according to the distances from the center to those intersection points and the vertices of the 3D model. Applying this method on ten categories of 3D models in PSB (Princeton Shape Benchmark), the results show that this approach not only reduces the processing time, but improves the retrieval accuracy.

Key words: 3D model retrieval, extended ray-based method, discounted cumulated gain, similarity measure, time complexity

摘要： 针对原始射线法特征提取时间较长、仅利用三角形面片问题，提出一种基于不相交平面束原理的扩展射线法。从质心均匀散射出一组射线与三角形面片相交，利用射线确定的不相交平面束定位交点;根据交点、顶点到质心的距离，建立检索模型以改善三维模型的检索效果。利用普林斯顿大学三维模型库的10类模型作为实验数据，实验结果表明：与原始射线法对比，扩展射线法不仅提高了特征提取速度，而且提高了检索准确率。

关键词: 三维模型检索, 扩展射线法, 折扣增益值, 相似性度量, 时间复杂度