Applied Underwater Acoustics

11.4. Detection

One of the most basic signal processing functions in underwater acoustics is signal detection: does a measurement contain only noise or both signal and noise? The definitions of signal and noise differ by application. For example, a sonar engineer may consider an active sonar echo as signal and sound arising from a moving sea surface as noise. However, an acoustician studying ambient noise characteristics views the sea-surface-generated sound as signal and considers as noise transient sounds such as active sonar echoes or air-gun pulses. The first step in signal detection is to define what signal is and what noise is for the case at hand.

Formally, signal detection is considered a binary hypothesis test [23,28] where one is to decide ...