基于计算机辅助教学领域中平面几何图形的识别和检索研究,提出一套可行的完整解决方案,并对手绘图美化、基本图元检测、显著性分析、位置关系描述和匹配度计算等关键问题进行分析.在深入分析几何图各级特征的同时,提出具有较强针对性的布局关系描述和复杂图形匹配的多种算法,使得几何图形最终得以直接用于内容检索,弥补了基于关键字检索技术在描述查询意图方面的不足.实验结果表明,本文提出的解决方案不仅可行,而且具有较高的准确度.

As there are increasing numbers of digital documents for education purpose, we realize that there is not a retrieval application for mathematic plane geometry images. In this paper, we propose a method for retrieving plane geometry figures (PGFs), which often appear in geometry books and digital documents. First, detecting algorithms are applied to detect common basic geometry shapes from a PGF image. Based on all basic shapes, we analyze the structural relationships between two basic shapes and combine some of them to a compound shape to build the PGF descriptor. Afterwards, we apply matching function to retrieve candidate PGF images with ranking. The great contribution of the paper is that we propose a structure analysis method to better describe the spatial relationships in such image composed of many overlapped shapes. Experimental results demonstrate that our analysis method and shape descriptor can obtain good retrieval results with relatively high effectiveness and efficiency.