A standard expression of underwater binocular vision for stereo matching

Abstract

A camera in an underwater stereo vision system conforms to a multi-layer refraction model, and the perspective projection camera model is invalid. Because the imaging light is refracted, the corresponding pixel does not conform to the traditional polar constraint, and the stereo matching methods must conduct a two-dimensional search. In this paper, a standard expression is proposed to reduce the search space to one dimension. Based on a light field, any specific underwater binocular stereo vision is converted to a standard setup in which the axes of two cameras are parallel and the image is expressed as the light field, the direction information image and the position image. We found and proved that the direction information image conforms to the rule of corresponding rows. With this standard expression, the stereo matching is efficiently conducted and the 3D information can be computed from the disparity map and the position image. In the experiment, an underwater binocular stereo vision system is developed and the proposed method is compared with the traditional method. The results confirm that the proposed method has several advantages of conciseness, correctness, efficiency, and generality.