Extraction of pulse repetition intervals from sperm whale click trains for ocean acoustic data mining.
The analysis of acoustic data from the ocean is a valuable tool to study free ranging cetaceans and anthropogenic noise. Due to the typically large volume of acquired data, there is a demand for automated analysis techniques. Many cetaceans produce acoustic pulses (echolocation clicks) with a pulse repetition interval (PRI) remaining nearly constant over several pulses. Analyzing these pulse trains is challenging because they are often interleaved. This article presents an algorithm that estimates a pulse's PRI with respect to neighboring pulses. It includes a deinterleaving step that operates via a spectral dissimilarity metric. The sperm whale (SW) produces trains with PRIs between 0.5 and 2 s. As a validation, the algorithm was used for the PRI-based identification of SW click trains with data from the NEMO-ONDE observatory that contained other pulsed sounds, mainly from ship propellers. Separation of files containing SW clicks with a medium and high signal to noise ratio from files containing other pulsed sounds gave an area under the receiver operating characteristic curve value of 0.96. This study demonstrates that PRI can be used for the automated identification of SW clicks and that deinterleaving via spectral dissimilarity contributes to algorithm performance.
Laboratori d'Aplicacions Bioacústiques, Universitat Politècnica de Catalunya (UPC, Barcelona Tech), 08800 Vilanova i la Geltrú, Spain.
Serge
S
Zaugg
Mike
M
van der Schaar
Ludwig
L
Houégnigan
Michel
M
André
D000162:Acoustics; D000465:Algorithms; D000818:Animals; D057225:Data Mining; D004455:Echolocation; D009792:Oceans and Seas; D010363:Pattern Recognition, Automated; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D059629:Signal-To-Noise Ratio; D013018:Sound Spectrography; D050661:Sperm Whale / Q000502:physiology*; D013997:Time Factors