Detection and automatic extraction of tonals buried in noise

Tonals are of importance to underwater target detection and recognition,and their automatic extraction is indispensable for unmanned passive sonar system.We obtain the receiver operating characteristic(ROC) of tonal detection with statistical signal analysis,and theoretically analyze the amplitude threshold for recognizing peaks automatically in the power spectrum with a certain probability of false alarm.We then propose a kind of adaptive threshold to meet the fluctuation of ambient noise background in engineering.The results of sea test data processing show that the adaptive threshold works better than the fixed threshold, thus bringing fairly good performance in toanl recognition and automatic extraction.