Stereo Calibration of Non-Overlapping FOV Cameras With Phase-Shifting Wedge Grating

Stereo cameras have been widely used in three-dimensional (3D) reconstruction, target ranging and environment perception. The calibration of stereo cameras is the key technology of vision system. Most of the existing methods are not flexible due to limitations of the size of the cameras' overlapping fields of view (FOV) and the degree of defocus. This paper presents a stereo calibration method in which the feature points on the target are globally encoded by the phase-coding method. Each feature point has a specific code, and the mapping relationship between image coordinates and world coordinates can be uniquely determined. So, the stereo cameras whether or not capture the same area of the target, both the camera coordinate systems can be unified under one global coordinate system. In addition, calibration can be accomplished when cameras are out of focus seriously, for the coding and extraction of feature points are phase-based. Simulations and experiments were carried out to prove flexibility and robustness of the proposed method.