An original 3D reconstruction method using a conical light and a camera in underwater caves

This paper presents a new structured light approach dedicated to 3D mapping of underwater galleries in karst aquifers. This kind of method is based on the projection of a light pattern onto the scene captured by a camera. Our originality comes from the projected pattern used, since unlike literature methods, our light projector is a simple conical diving light. With a light cone, the recovered pattern in the image is a closed 2D curve we extract with a light contour detection method we have developed. A specific calibration method has also been created to estimate the cone geometry with respect to the camera. Therefore, we get a calibrated projector-camera pair, we can use to find matches between projected and recovered patterns. Our last contribution is the recovery of 3D data by triangulation using the camera cone relationship and the extracted closed 2D curve. The experimental results that will be presented in this article show the feasibility of the method.