Stereo-pair processing in a three-dimensional laser display system

The stereoscopic videoprojector developed at our laboratory is based on the simultaneous projection of the left and right images of a stereo-pair along two orthogonal polarization directions of a laser beam. The horizontal scanning system, which deflects four lines simultaneously, led to the design of a specific acousto-electro-optical modulation device using three independent command variables to control four pixel intensities. This introduces a degradation of the perceived images that we strive to minimize using the information redundancy in the images. In this paper, we first present the principle of operation and the optical modulation device. Then, an optimal solution for the computation of the command variables from the original stereo-pair pixel intensities is proposed and developed. The chosen mathematical criterion is the minimization of the quadratic error between the perceived and original pixel intensities. The study of the visual degradation introduced in the images by the proposed stereo-pair processing leads to the distinction of two kinds of phenomena: the mixing of the pixel intensities in the same image and the mixing of the pixel intensities between the left and right views. The simulations realized with reference images allow a quantitative evaluation of their relative proportions and of the final image quality.