Preliminary Result on Underwater 3-Dimensional Reconstruction Using Imaging Sonar

This paper proposes a practical 3D object reconstruction method using an underwater imaging sonar. In order to reconstruct the 3D object, three methods are utilized. Firstly, the vertical beam-angle of imaging sonar is modified to narrow angle to reduce an uncertainty of estimated 3D position. The wide vertical beam-angle makes the incorrect estimation result about the 3D position of the reconstructed object. Secondly, simple noise filtering and range detection methods are designed to extract a distance from the sonar image. Lastly, a low pass filter is adopted to estimate a probability of voxel occupancy. To demonstrate the proposed methods, 3D reconstruction for three sample objects was performed in a basin and results are explained.