基于立体视觉的高精度标定与测量方法

立体视觉测量系统中，光学系统产生的畸变使目标的成像偏离了理论成像点，导致系统产生测量误差。针对提高系统测量精度的问题，提出一种基于立体视觉的测量方法。首先，根据标定板上各角点的像素分辨率，拟合整个成像平面的四次多项式，且多项式的系数与物体到相机的距离成比例；然后，应用双目测距原理，测量被测物体的纵向距离；最后，基于所得的多项式，应用单目相机测量待测物体的横向尺寸。实验结果表明，对于所提方法，当物体距离相机5 m以内时，其纵向距离误差可以减小到5%以内；当物体距离相机1 m时，其横向宽度测量误差在0.5 mm内，逼近理论最高分辨率。

High-precision calibration and measurement method based on stereo vision

In stereo vision measurement system, the distortion caused by the optical system makes imaging of target deviate from the theoretical imaging point, which results in measurement error of system. In order to improve the accuracy of the measuring system, a new measurement method based on stereo vision was proposed. Firstly, a quartic polynomial on the whole imaging plane was fitted through the pixel resolution of each angular point on the calibration board, the coefficient of the fitted polynomial was proportional to the distance from the object to the camera. Then, the longitudinal distance of the detected object was measured by using the measuring distance principle of binocular model. Finally, based on the obtained polynomial, the monocular camera was used to measure the transverse dimension of the detected object. The experimental results show that, when the distance between the object and the camera is within 5 m, the longitudinal distance error of the proposed method can be reduced to less than 5%. And when the object is 1 m away from the camera, the measurement error of transverse width of the proposed method is within 0.5 mm, which approaches to the theoretical highest resolution.