A Multireceiver SAS Imaging Algorithm and Optimization

Seafloor mapping is an important related to oceanic engineering. However, traditional side-scan, multibeam, and sub-bottom sonar systems generate acoustic images having insufficient resolution owing to their restricted array aperture. To overcome this limitation, synthetic aperture sonar (SAS) systems create a virtual aperture without any limitation. Hence, a SAS system can generate acoustic images having substantially increased resolution those generated using conventional mapping and imaging techniques. In this study, we propose a SAS imaging method that employs an analytical system function. The key steps involved in the presented method are bulk focusing and coordinate transformation. Because the two-dimensional raw signal is characterized using a large amount of data, the imaging algorithm involves extensive computations. To decrease this computational load, we optimize the presented algorithm using parallel algorithms including Intel® Math Kernel Library (Intel® MKL) and OpenMP. This optimization strategy effectively reduces the computation load involved in the presented algorithm compared to that involved in the benchmark method of back projection focusing. Furthermore, the presented method outperforms Zhang’s method. At the same time, the high-resolution multireceiver SAS reconstruction results are still produced by using given technology. Therefore, the presented method can be readily employed for seafloor mapping.