Transient Signal Detection on the Basis of Energy and Zero Crossing Detectors

In underwater passive surveillance systems, narrowband displays help in classifying tonal sounds but transient sounds are largely classified through audition. Over the years, the intensity of tonal has been reduced by ship/submarine constructors, and so their use for classifying underwater targets has become diminished. Transient sounds are harder to disguise and are becoming more useful for detecting targets. In the naval scenario, quick and accurate detection of transient signals offers an advantage of longer response time to thwart an enemy attack. Underwater transients from manmade objects and biologics are very rich in structure and detail, very diverse in terms of duration, highly non-stationary, and often mixed with multipath. The need is for automatic detection and classification of underwater transients, in order to assist the overburdened sonar operator. Recently, the work on wavelet transform for transient signal detection is carried out but the problem with these detectors is that these are computationally very expensive. We are presenting a new kind of detector which works on energy of the segments and the corresponding mean of the zero crossings of the signal.