Underwater Scanning Using LiDAR

The underwater vehicle-manipulator system (UVMS) is a typical platform for carrying sensors of underwater scanning. One of these sensors is Light Detection And Ranging (LiDAR). One of the further developments of LiDAR is Oceanic LiDAR or O-LiDAR. Compared with acoustic methods, optical methods which LiDAR has classified provide high resolution and accuracy. Our goal is to develop a LiDAR sensor to be able to scan underwater surfaces and integrate them into UVMS. There are 2 methods that we use, namely the submerged method and the airborne method. The Submerged LiDAR Scanning method is to insert the device into a watertight container, which is then placed in the water with the object to be detected. The Airborne LiDAR Scanning method is different from the previous method. In this method, the device is not placed in a special container, but placed above the water surface. In testing, we used 2 LiDAR sensors, the RPLiDAR Slamtec A2M8 and iPhone LiDAR. After testing with the submerged method, it turns out that the two sensors cannot detect objects. There is a possibility that the laser beam failed to penetrate the container. Then testing was carried out using the airborne method, but the results still failed to detect the object. Our hypothesis regarding the cause of the failure of the sensor to detect objects in the water is due to the water refraction factor and also the color of the laser light used. Based on these results and discussions, it can be concluded that the LiDAR A2M8 and iPhone LiDAR are not able to detect objects in the water.