一种高效的基于约束网络的工程图符号识别方法

将工程图中所有符号的几何特征转换为一个约束网格，用结点记录判断条件，边指示判断次序，实现以层次化约束判断为核心的过滤式识别方法，基于逐步简化的思想，该方法引入多层优先级和边属性的定义，通过优先级调整和边属性查询的配合，优化网络搜索；通过将巳经过约束检查的图元编号记录在结点中而大幅度减少图元遍历和判断。该方法应用在建筑工程图识别中效率较高，对符号种类多、图低内容复杂等情况适应能力较强。

A Highly-Efficient Constraint-Network-Based Approach for Symbol Recognition of Engineering Drawings

This paper converts the geometrical features of all the symbols in engineering drawings into one constraint network, whose nodes contain the test conditions and edges denote the judgement order, and implements the new filtration recognition algorithm based on the hierarchical condition testing. This approach is guided by the thought of stepwise simplification,introduces multi layer priorities, and optimizes the flow of network traversal through defining edge attributes cooperated with priority adjustment. By using the procedure of recording the indices of primitives that have successfully passed former condition test in certain nodes, the times of primitive traversal and judgement are reduced greatly. The approach of the paper is implemented in one architectural drawing recognition system, embodies high efficiency and powerful adaptability, especially for the situation of large quantity of symbol types or the case of complicated drawing.