Projective Rectification with Minimal Geometric Distortion

There has been an increasing interest in the 3D imaging in the fields of entertainment, simulation, medicine, 3D visual communication, 3D tele-robotics, and 3D TV to augment the reality of presence or to provide vivid and accurate structure information. In order to provide vivid information in these and other 3D applications, efficient techniques to generate, store, and view the stereoscopic video are essential. While many methods are available for acquiring stereoscopic video, the images pairs obtained might not be in rectified form. Therefore, rectification is usually needed to support comfortable viewing and effective compression for storage and transmission. Projective geometry has been proved to be a useful tool for solving the rectification problem without camera calibration. However, if the matrices used for projective rectification (homographies) are not constrained properly, the rectification process can cause great geometric distortion. For visual applications, rectification with minimum geometry distortion should be pursued. In this chapter, we propose an improved algorithm to minimize the distortion by combining a newly developed projective transform with a properly chosen shearing transform. This new method is equipped with flexibility and can be adapted to various imaging models. Experimental data show that the proposed method works quite well for all the image pairs taken different imaging conditions. Comparison with other available method based on visual inspection and numerical data demonstrates the superiority of the new approach.