title: Spectrogram denoising and automated extraction of the fundamental frequency variation of dolphin whistles.
abstract: Marine mammal vocalizations are often analyzed using time-frequency representations (TFRs) which highlight their nonstationarities. One commonly used TFR is the spectrogram. The characteristic spectrogram time-frequency (TF) contours of marine mammal vocalizations play a significant role in whistle classification and individual or group identification. A major hurdle in the robust automated extraction of TF contours from spectrograms is underwater noise. An image-based algorithm has been developed for denoising and extraction of TF contours from noisy underwater recordings. An objective procedure for measuring the accuracy of extracted spectrogram contours is also proposed. This method is shown to perform well when dealing with the challenging problem of denoising broadband transients commonly encountered in warm shallow waters inhabited by snapping shrimp. Furthermore, it would also be useful with other types of broadband transient noise.
authors.affiliation: Department of Electrical and Computer Engineering, National University of Singapore, Singapore. eleongsh@nus.edu.sg
authors.forename: Asitha
authors.initials: A
authors.lastname: Mallawaarachchi
authors.forename: S H
authors.initials: SH
authors.lastname: Ong
authors.forename: Mandar
authors.initials: M
authors.lastname: Chitre
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Taylor
mesh_terms: D000465:Algorithms; D000818:Animals; D016477:Artifacts; D050681:Bottle-Nosed Dolphin / Q000502:physiology; D004289:Dolphins / Q000502:physiology*; D008954:Models, Biological; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D012846:Singapore; D013018:Sound Spectrography; D013997:Time Factors; D014828:Vocalization, Animal