Research on High-precision Calibration and Measurement Method based on Stereo Vision

In stereo vision measurement system, distortion caused by the optical system makes images of targets deviate from theoretical imaging points, which results in measurement error of the system. In order to improve the measurement accuracy of the system, a quartic polynomial on the whole image plane is obtained through fitting the pixel resolution of each angular point on calibration board, the coefficient of which is proportional to the distance from the object to the camera. Then, we utilize binocular vision technology to calculate the distance of the detected object, and monocular vision to measure its transverse dimension. Experimental results show that, when the distance between the object and the camera is within 10m, the distance error can be reduced to less than 5%. And when the object is 1 meter away from the camera, the measuring error of the transverse width of the object is within 0.5mm, which approaches to the theoretical highest resolution.