基于圆形模式平面标靶的高精度相机标定方法

High-Precision Camera Calibration Method Using Planar Target with Circular Dot Patterns

相机标定是三维视觉精确测量过程的一个关键步骤.圆形模式平面标靶是最常见的一种标定工具,具有制造简单,受环境光和噪声影响较小的优点.唯一的不足是由于镜头畸变和透视偏差,成像的椭圆中心并非标靶圆心的特征对应点,因此利用椭圆中心作为标定特征点,降低了相机的标定精度.针对这个问题,本文提出了一种同时矫正透视和畸变偏差的方法,从而得到精确的圆心成像点,获得高精度的标定结果.模拟实验和真实图像标定结果验证了算法的正确性和有效性.另外,本方法提出的透视和畸变矫正方法独立于相机内部参数估计过程,因此可以应用于更复杂的相机模型.

Camera calibration is a key procedure for accurate three-dimensional visual measurement.Planar target with Circular dot patterns is a commonly utilized calibration tools with the advantages of manufacturing simplicity and modest resistance to ambient light and noise.However,due to lens distortion and perspective bias its ellipse center does not overlap with the feature correspondence point in most cases.Calibration accuracy will have to be sacrificed if we align them to one single point.To solve this problem,a method is proposed in this research for simultaneous correction of both perspective and distortion bias to get the lens center and,subsequently,accurate calibration.The results of stimulative experiments and real image processing prove the effectiveness of the proposed method.In addition the method for perspective and distortion correction is independent of the camera internal parameter estimation process,which indicates its validity when applied to more complex camera models.