当前主流的在线高精度PCB 裸板缺陷AOI 检测系统均采用基于轮廓矢量化分析比对方法，圆弧探测是实现轮廓矢量化的关键环节。本文提出一种快速的圆弧探测方法，首先采用DP(Douglas-Peucker)算法对轮廓进行曲线抽稀处理，将轮廓分割为直线段基元并计算法向角，然后依次计算各相邻直线段基元的法向角偏差之和，并与基元中点位置值一起形成法向角变换曲线，再次采用DP 算法检测变换曲线中的直线段即可完成圆弧探测。本文将圆弧探测简化为两次直线探测，算法复杂度为O(n)，具有非常高的计算效率。实验结果表明，本文方法与Halcon商业软件中的圆弧检测算法相比，准确率更高且耗时更少。

The most popular online high-precision Automatic Optical Inspection (AOI) detection system for PCB bare board adopts the inspection method based on contour vectorization and comparison, and arc detection is the key of realizing the contour vectorization. A new fast arc detection method is proposed. Firstly, segmentation primitives are obtained from contours by Douglas-Peucker polyline simplification algorithm and their normal angles are calculated.Then, the sum of difference between normal angles of each two adjacent primitives is calculated, which is used to build the normal angle transformation curve with the position of mid-point of primitive. Finally, DP algorithm is used again to detect the line segments in normal angle transformation curve to implement arc detection. The proposed algorithm simplifies the arc detection into two times line segment detection, and the complexity is O(n). Experimental results show that the proposed algorithm owns higher accuracy and lower cost time in comparison with the same module of Halcon software.