Complete calibration of a structure-uniform stereovision sensor with free-position planar pattern

We present a novel structure-uniform stereovision sensor for variable 3D inspection tasks. In this paper, the mathematical model of the stereovision sensor is established. A flexible approach to estimate all the primitive parameters of the stereovision sensor with free-position planar pattern is proposed. In this technique, without restriction to the moving of the planar reference object, all the camera parameters with coefficient of lens radial and tangential distortion can be readily calibrated, and based on the 3D measurement model of stereovision sensor, the sensor parameters can be optimized with the feature points constraint algorithm simultaneously. The proposed approach greatly reduces the cost of the calibration equipment, and it is flexible and practical for the vision measurement. It shows that this method has high precision by experiment, and the measured relative error of space length excels 0.3%.