Extraction and organization of metadata feature for underwater target recognition by sonar echoes

To recognize an underwater target precisely is always a very difficult task for the navy due to the interference-filled under sea. Sonar is the most efficient way to detect items in the underwater world but the recognition still depends on sonarman. As well known, the feature extraction metho is the key of automatic target recognition. In this paper, a model 2-dimensional metadata of echo is defined, which is based on echo's frequency and temporal domain information. It contains two features, energy difference and zero cross rate. This paper concentrated on extraction of every feature and the organization method. Experiment results show the effectiveness of the presented approach.