(A) biprism stereo camera system

Abstract

In sterro vision, the stereo disparity between the two images from two distinct viewpoints is a powerful cue to 3D shapes and pose estimation. Some geometric difference between stereo images is unavoidable. For stereo images acquired by the two cameras, the focal lengths and zoom levels of the cameras are often slightly different. Differences in the optical properties of the two cameras cause intensity differences between corresponding points in a stereo images. It is desired that a stereo camera system can obtain a pair of images in a single shot and through a single lens so that unwanted geometric nad intensity differneces between the images could be avoided. This thesis proposes a novel and practical stereo camera system that uses only one camera and a biprism placed in front of the camera. The equivalent of a stereo pair of images is formed as the left and right halves of a single CCD image using a biprism. An advantage of the geometrical set-up is that corresponding features lie on the same scanline automatically. The single camera and biprism have led to a simple stereo system for which coorespondence is very easy and which is accurate for nearby objects in a small field of view. Since we use only a single lens, calibration of the system is greatly simplified. We can reconstruct the 3D strcture using only the disparity between the corresponding points. Manufacturing the biprism generally, the surface of the biprism has a curvature, which is a factor of the variation of angle. The image distortion is produced by the variation of angle. We introduce an method that can calibrate a deviation of biprism for compensating the distortion. We present a method that can improve the depth accuracy through the compensation and the modeling of the distortion. The image quality is deteriorated by a chromatic aberration. We present a method that can minimize the chromatic aberration to improve the image quality and the effect of the chromatic aberration according...