中文摘要：

针对视觉跟踪式自准直仪中如何快速精确提取十字线的问题,根据图像灰度特性及灰度分布特点,提出了一种基于视觉跟踪式自准直仪的十字线提取算法。对图像进行预处理后,进行轮廓提取获得十字线像素级边缘,采用改进的一阶微分期望法精确确定十字线亚像素边缘,利用直线拟合获得边缘直线方程,从而获得精确的十字线中心。实验结果表明,该方法具有较高的提取精度,并且计算简便、实时性好、适用性强。

英文摘要：

To extract the reticle in the autocollimator fast and accurately,an extraction technology is proposed.At first,contour extraction method is used to get the coarse position after the image preprocessing.Then an improved subpixel edge detector using first-order derivative expectation is used to get the precise position.Finally,straight line fitting method is applied and the center of the crossing line is obtained.The experiment results show that the proposed algorithm can extract the edge of the crossing line precisely,and it has the characteristics of good real-time,simple calculation and strong adaptability.