title: Dolphin biosonar target detection in noise: wrap up of a past experiment.
abstract: The target detection capability of bottlenose dolphins in the presence of artificial masking noise was first studied by Au and Penner [J. Acoust. Soc. Am. 70, 687-693 (1981)] in which the dolphins' target detection threshold was determined as a function of the ratio of the echo energy flux density and the estimated received noise spectral density. Such a metric was commonly used in human psychoacoustics despite the fact that the echo energy flux density is not compatible with noise spectral density which is averaged intensity per Hz. Since the earlier detection in noise studies, two important parameters, the dolphin integration time applicable to broadband clicks and the dolphin's auditory filter shape, were determined. The inclusion of these two parameters allows for the estimation of the received energy flux density of the masking noise so that the dolphin target detection can now be determined as a function of the ratio of the received energy of the echo over the received noise energy. Using an integration time of 264 μs and an auditory bandwidth of 16.7 kHz, the ratio of the echo energy to noise energy at the target detection threshold is approximately 1 dB.
authors.affiliation: Hawaii Institute of Marine Biology, P.O. Box 1106, Kailua, Hawaii 96734.
authors.forename: Whitlow W L
authors.initials: WW
authors.lastname: Au
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000818:Animals; D001307:Auditory Perception; D001309:Auditory Threshold; D050681:Bottle-Nosed Dolphin / Q000502:physiology / Q000523:psychology*; D004455:Echolocation; D009038:Motion; D009622:Noise / Q000009:adverse effects*; D010470:Perceptual Masking; D011312:Pressure; D017603:Signal Detection, Psychological; D012815:Signal Processing, Computer-Assisted; D013016:Sound; D013018:Sound Spectrography; D013997:Time Factors