An approach to lofargram spectrum line detection based on the spectrum line feature function

In field of passive signal detection, lofargram is widely used to process and analyze the received noise signal. Aiming at the problem of lofargram spectrum line detection, a new method named frequency domain accumulate detection algorithm based on spectrum line feature is designed. The key point of the method is moving observation window in the frequency axis; using the multistage decision algorithm to calculate the optimal solution of every window; and accumulating the counter of every image point. That is, if the function value of the optimal path is greater than threshold, then the counter of every image point on the optimal path increases one. The image point has higher probability to be a spectrum line point if the number of the point's counter is larger. Simulation research indicates that this method can detect several spectrum lines correctly when the SNR is low on the lofargram. The method is verified with sea trial data. So it is valuable in the field of remote detection of underwater radiant target.