Detection of creak clicks of sperm whales in low SNR conditions

A function of a nonlinear operator referred to as Teager-Kaiser Energy operator is described to detect creak clicks of sperm whales in adverse conditions. Clicks are considered as a sum of transient signals mixed with interference signals and background Gaussian noise of unknown variance. The method has been applied to synthetic as well as to real recordings of creak clicks. On synthetic data the detection rate gives excellent results. For low SNR a detection rate close to 100% is achieved while it works very well in detecting clicks in real creak sounds.