An Improved Method for Stereo Camera Calibration

Using stereo cameras for visualization and three-dimensional reconstruction is highly applied, because in addition to the interior orientation,relative orientation parameters are stable during the imaging. Therefore these parameters can be used as stable values in next processing levels for eppipolar resampling in stereo vision, automatic image stitching in creating stereo panorama, and extracting geometry information.In the common methods, to calibrate stereo camera, the exterior and interior orientation parameters for each camera lenses were determined by solving bundle adjustment. After that, the relative orientation parameters of the two lenses were calculated by using the relationbetween the two lenses.This method is not highly persistent,because of the considerable noise in estimation of the exterior orientation parameters.In our method, an improved method to calibrate the stereo cameras is provided and evaluated in which the relative orientation parameters were determined directly to calibrate the stereo cameras using constrained bundle adjustment.The experiments indicated that to calibrate the stereo camera, our method has improved up to 20 percents more than the common method in relative orientation parameters’ standard deviation.