3D-Sonar image formation and shape recognition techniques

In future developments of AUV systems 3D image processing techniques will gain in importance. The high resolution 3D-Sonar can be considered as the ldquoeyerdquo of the AUV which provides acoustical information utilized for the detection and classification of anomalies, e.g. at ships hulls. Therefore, the investigations presented include the simulation of underwater scenes, object shapes and AUV movements as well as the modelling of the acoustical system performance. The obtained beam signals provide the input to the 3D image formation and shape recognition algorithms. Beside conventional 3D interpolation and voxel image formation techniques we propose a novel image formation approach by exploiting the maximum of each beam signal. Moreover, efficient noise suppression algorithms are developed and validated by employing multi-beam/multi-aspect imaging. Finally, the proposed 3D image formation technique is computationally efficient, robust against noise and allows the application of conventional 2D image processing algorithms.