A trace extraction technique for fast moving underwater target

Trace extraction of fast moving underwater target is an interesting topic in passive sonar detection. The application area includes harbor protection, torpedo alarming, and so on. The signal processing methods can be used are automatic target tracking (ATT) and target moving analysis (TMA). In this paper, the trace extraction problem is considered as two dimensional image processing problem. The raw data come from the time-bearing history of sonar post processing. The trace of moving targets will be extracted step by step and the random blank pixels and the background noise will be filtered. Some data sieves are established to take away random blank pixels and any accidentally appeared target-like trace. A new algorithm, which is actually a combination of OTA (order truncate average) technique and median filtering, is derived as a data sieve to equalize the background noise. A double check procedure for grazing angle and the change rate of signal to noise ratio is taken to identify the trace of fast moving targets.