Research On Three-dimensional Underwater Acoustical Imaging And Sonar Image Processing Technology

Three-dimensional underwater acoustical imaging is widely utilized in underwater investigation, target detection and classification. Three-dimensional (3-D) imaging sonar can obtain 3-D images of underwater world directly which is different from sidescan sonar. The study of underwater acoustical imaging techniques and 3-D acoustical image processing is important for the design and development of 3-D imaging sonar.This paper is based on the item of position extraction of 3-D underwater objects. The purpose of this thesis is to study the feature extraction techniques of underwater objects based on the high-resolution imaging sonar. Firstly, the concept and characters of basic acoustical imaging is introduced, with emphasis on 2-D FFT beamforming, and simulation results of the focus beamforming and Dolph-Chebyshev weighting of different condition are discussed. Secondly, the superquadric model and the segmentation and modeling algorithm of 3-D sonar images based on the range data are researched. Finally, the results of 3-D acoustic imaging simulation of cylinder target,sphere target and mixed target in underwater environment using simple point-scatter models are made, which provide the range data for segmentation and modeling from sonar images. Results from the simulation prove the validity of the recover and select algorithm.