Underwater 3D reconstruction based on laser line scanning

This paper proposes an underwater 3D reconstruction method based on laser line scanning. 3D reconstruction of underwater target is an important technology in ocean development. Due to the complicated underwater environment, underwater 3D reconstruction is still a challenge. The traditional underwater object detection is mainly based on acoustic technology, but acoustic technology can't meet the demands of high-precision underwater reconstruction. Laser line scanning is a popular technology which can be applied into complex underwater environments. It has stable antijamming capability and high-precision scanning capability which can help us to finish 3D reconstruction delicately. In our method, We combine some advanced methods to finish this reconstruction. There are two important links. The first one is calibration method called direct calibration. This method can get the relationship between 2D pix coordinate and 3D world coordinate directly, so we don't need to calculate complex camera parameters. The second one is extraction of line laser. Getting clear images and processing them well is beneficial to extract the center line of the laser, so we use smoothing to reduce the interferences first, then direction template technology combined with gray centroid method is used to get the information of center line. In order to verify the correctness of this methods, experiment was done on the land firstly and got a good result. Then the experiment was done in a sink. We use a disk and a keyboard as the target. With our adjustment, we have got a clear shape of the underwater object. At the same time, structure from motion is used as a compared method.