Measuring the off-axis angle and the rotational movements of phonating sperm whales using a single hydrophone

Adam, Olivier; Lopatka, Maciej; Motsch, Jean-François

doi:10.1121/1.2184987

Cited by 14 publications

(17 citation statements)

References 21 publications

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“…The reliability of this technique is, however, considerably complicated by the fact that the pulse structure of clicks is highly dependent on the aspect of the whale relative to the recorder ͑Zimmer et al., 2005b;Laplanche et al, 2006͒. Unless the recorder is on or near the anterior-posterior axis of the whale, then intermediate pulses can occur, making it hard to resolve the "true" IPI ͑Fig. 2͒.…”

Section: Introductionmentioning

confidence: 99%

Measuring inter-pulse intervals in sperm whale clicks: Consistency of automatic estimation methods

Antunes

Rendell

Gordon

2010

The Journal of the Acoustical Society of America

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Sperm whale clicks are characterized by a multi-pulsed structure. The time lag between consecutive pulses, i.e., the inter-pulse interval (IPI), is related to the size of the sound production organ such that its measurement provides a means to acoustically estimate the size of individual whales. Due to off-axis effects the identification of pulses is, however, not always straightforward, and automatic measurement methods provide not only more objective estimation, but may also facilitate IPI estimation in cases where single click measurements are ambiguous. In particular, averaging measurements over a time series of clicks from the same whale could enhance the discrimination of time invariant pulses. The authors developed two automatic methods of automatic IPI measurement based on waveform and autocorrelation averaging and compared their accuracy and consistency with other previously used methods. Manual measurement by an experienced operator provided the most self-consistent estimates. The autocorrelation averaging technique had the best overall performance of the automated methods achieving a very similar performance to manual measurement. On some recordings cepstrum averaging methods converged when autocorrelation did not. Therefore, applying both of these automated methods and choosing the best of the two are recommended.

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Section: Introductionmentioning

confidence: 99%

Measuring inter-pulse intervals in sperm whale clicks: Consistency of automatic estimation methods

Antunes

Rendell

Gordon

2010

The Journal of the Acoustical Society of America

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“…Other click components ͑resulting from further reflections in the head and other exit points͒ are also present ͑Møhl, 2001͒, but they are not required or considered here. Since the measured delay between the p0 and p1 pulses depends on the orientation of the whale ͑Zimmer et al., 2005a;Laplanche et al, 2006͒, it can be used to recover roll.…”

Section: Introductionmentioning

confidence: 99%

Sperm whale three-dimensional track, swim orientation, beam pattern, and click levels observed on bottom-mounted hydrophones

Nosal

Frazer

2007

The Journal of the Acoustical Society of America

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In an earlier paper [Nosal and Frazer Appl. Acoust. 61, 1187-1201 (2006)], a sperm whale was tracked in three-dimensions using direct and surface-reflected time differences (DRTD) of clicks recorded on five bottom-mounted hydrophones, a passive method that is robust to timing errors between hydrophones. This paper refines the DRTD method and combines it with a time of (direct) arrival method to improve the accuracy of the track. The position and origin time of each click having been estimated, pitch and yaw are then obtained by assuming the main axis of the whale is tangent to the track. Roll is then found by applying the bent horn model of sperm whale phonation, in which each click is composed of two pulses, p0 and p1, that exit the whale at different points. With instantaneous pitch, roll, and yaw estimated from time differences, amplitudes are then used to estimate the beam patterns of the p0 and p1 pulses. The resulting beam patterns independently confirm those obtained by Zimmer et al. [J. Acoust. Soc. Am. 117, 1473-1485 (2005); 118, 3337-3345 (2005)] with a very different experimental setup. A method for estimating relative click levels is presented and used to find that click levels decrease toward the end of a click series, prior to the "creak" associated with prey capture.

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“…[8] have suggested that sperm whales would, at depth, make an asymmetric scan of the surrounding water and that during the search phase sperm whales would methodically scan a cone-shaped mass of water searching for prey. This scan would suggest that each sperm whale click is generated to aim in a specific direction at a specific range.…”

Section: Behavior Analysismentioning

confidence: 99%

“…level control: sperm whales would click slowly at a high source level and faster at a lower source level. In [8] the proposed echolocation model specifies that sperm whales would aim at closer targets while emitting clicks with lower source level at higher rhythmic rate, and aim at farther targets emitting clicks with higher source level and slower rhythmic rate. Finally, [9], [10] suggests that sperm whales move at constant heading and speed while hunting.…”

Section: Behavior Analysismentioning

confidence: 99%

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High level automatic structuration of ocean passive data : From click sequence modulations to whale behavior analyses

Caudal

Glotin

2008

2008 New Trends for Environmental Monitoring Using Passive Systems

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This paper discusses on estimating the behavior of a sperm whale using hydrophones recordings thanks to a set of features extracted from a real-time passive underwater acoustic tracking algorithm for multiple emitting whales. Acoustic localization permits to study whales' behavior in deep water (several hundreds of meters) without infering with the environment. Here, we use a real-time multiple tracking algorithm, which provides a localization of one or several sperm whales. Thanks to the positions coordinates and the audio files, we are able to automatically label the signal and to extract different features such as the speed, energy of the clicks, Inter-Click-Interval (ICI)... These features allow us to cross-analyse the whale behavior (foraging , hunting, ingestion) and to see the influence of each parameters and the dependency between them. Finally, we generate a XML file for description and efficient access of deep ocean sound records for cetacean studies, which leads to index and structure the audio files. Thus, the behavior study is facilitated choosing and accessing the corresponding index in the recording. The complete method is processed on real data from the NUWC 1 and the AUTEC 2 . As an illustration, we process the algorithm on a one whale case and study the correlation between the features and the whale behavior during the diving.

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Measuring the off-axis angle and the rotational movements of phonating sperm whales using a single hydrophone

Abstract: OATAO is an o pen ac cess re pository that c ollects th e work of To ulouse re searchers a nd makes it freely available over the web where possible.Any correspondence concerning this service should be sent to the repository

Cited by 14 publications

References 21 publications

Measuring inter-pulse intervals in sperm whale clicks: Consistency of automatic estimation methods

Measuring inter-pulse intervals in sperm whale clicks: Consistency of automatic estimation methods

Sperm whale three-dimensional track, swim orientation, beam pattern, and click levels observed on bottom-mounted hydrophones

High level automatic structuration of ocean passive data : From click sequence modulations to whale behavior analyses

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