Biprism distortion modeling and calibration for a single-lens stereovision system

Biprism-based single-lens stereovision systems have several advantages over conventional two-camera systems, which has made them popular in recent years. However, employing a biprism in front of the camera will induce additional unique distortion in the image, which cannot be adequately represented by the existing distortion models, making it is difficult to calibrate or correct. In this work, a parametric biprism distortion model aiming to correct this biprism distortion is developed and evaluated. The estimation of the model starts with a general bivariate polynomial and is then refined based on distortion properties. These properties are determined by the geometrical analysis of the distortion formation in the system. This refined model is evaluated in two ways: distortion map data fitting and virtual camera calibration. Both simulation and actual experiments are carried out to show the feasibility of the proposed distortion model and the improvements in calibration accuracy and depth recovery compared with the existing distortion models.