相机标定的精度影响实验分析

Influence experimental analysis for camera calibration accuracy

相机标定是机器视觉中的必要步骤,标定效果直接影响后续的测量精度。在张正友标定方法的基础上,对棋盘格尺寸、标定图片数量、棋盘格打印方式3个方面进行实验分析,实验过程中通过控制变量法进行对比实验。实验结果表明,棋盘格尺寸选择10~15 mm时标定效果较好;当棋盘格角点数目相同时,棋盘格尺寸越大,标定所需的图片数量越多;当棋盘格尺寸相同时,角点数目越多,标定所需的图片数量就越少;彩印的标定棋盘格在有效焦距、主点坐标以及重投影误差方面都比普通打印的精度高,且与实际值的误差维持在5个像素内,波动较小。实验结论为提高相机标定精度提供了有效参考。

Camera calibration is a necessary step in machine vision,the calibration effect directly affects the subsequent measurement accuracy.This article performs experimental analysis on the three aspects of checkerboard size,number of calibration pictures,and checkerboard printing method based on Zhang Zhengyou’s calibration method.During the experiment,contrast experiment is performed by controlled variable method.Experiment results show that the calibration effect is better when the checkerboard size is 10~15 mm.When the number of corners of the chessboard is the same,the larger the size of the chessboard,the more the number of calibration images needed,when the size of the chessboard is the same,the more the number of corners,the less the number of calibration images needed;The color-printed calibration checkerboard has higher accuracy than ordinary printing in terms of effective focal length,principal point coordinates and re-projection errors,and the error with the actual value is maintained in 5 pixels with the small fluctuation.The experimental conclusions provide an effective reference for improving the accuracy of camera calibration.