基于平面变换的高精度相机标定方法

针对传统方法未考虑透视偏差的存在，提取椭圆圆心作为真实物理圆心投影点造成相机标定误差的问题，提出了一种基于平面变换的高精度相机标定方法。提取标定板内外边框上的角点，对标定板进行平面变换，将标记点由椭圆投影成近似的标准圆；利用图像矩提取标准圆圆心的坐标，投影回原标定板平面，得到标记点实际圆心的像素坐标；根据圆形标记点实际圆心的坐标，利用张正友标定法完成相机标定。实验结果表明:与传统方法相比，所提方法将相机标定的误差降低了66.169%，有效提高了相机标定的精度。 

Calibration method for high precision camera based on plane transformation

Traditional methods do not consider the existence of perspective deviation, and usually extract the center of the ellipse as the projection point of a real physical center, resulting in camera calibration errors. A calibration method for high precision cameras was proposed based on plane transformation. The corner points on the inner and outer borders of the calibration plate were extracted to carry out the plane transformation of the calibration plate, and the marked points were projected from ellipses into approximate standard circles. The coordinates of the center of the standard circle were extracted by image moments, and were projected back to the plane of the original calibration plate to obtain the pixel coordinates of the actual center of the marked points. According to the coordinates of the actual center of the circular markers, the Zhang Zhengyou calibration method was used to complete the camera calibration. Experimental results show that compared thus the traditional method, the proposed method reduced the camera calibration error by 66.169%, thus effectively improving the camera calibration accuracy.