Feasibility study of noise reduction for imaging sonar based on time-domain filtering

Underwater sonar image can be obtained by the multi-beam imaging sonar. Because of its high frame rate, the imaging sonar can be used for underwater survey especially in turbid water condition. However, the sonar image is generally degraded by the speckle noise. In this paper, we propose a realtime noise reduction algorithm by using the recursive least square algorithm, which is one of the adaptive filters. Through experiments, the performance of the proposed algorithm is analyzed and its feasibility is determined. Also the difference between the proposed algorithm and the conventional noise reduction algorithms that are based on spatial-domain filters are discussed.