Multi-Detect Algorithm for multibeam sonar data

When conducting hydrographic surveys the surveyor has to choose between storing just the bottom detections or the entire water column data. The former may result in vital information being lost, while the latter often requires very large storage capability. This paper presents the Multi-Detect Algorithm (MDA), a method for real-time detection of objects in the water column as well as the seafloor beneath. This method is designed to work in conjunction with existing bottom detection algorithms, as a predetection procedure preceding the normal bottom detection. Results from three different scenarios are used to demonstrate that MDA is able to extract more information from the water column than a typical bottom detection algorithm (BDA). Also presented is data from complex underwater objects and a challenging multipath environment. MDA is shown to offer a viable alternative to storage and postprocessing of water column data, and give more details on complex targets and flexibility in challenging environments.