Automatic detection of African elephant (Loxodonta africana) infrasonic vocalisations from recordings

Abstract

Published online xxxRecordings of elephant vocalisations can be used to determine the size and composition of the herd, the sexual state, as well as the emotional condition of an elephant. Manual analysis of recordings (by listening to these and by visual inspection of spectrograms) to locate vocalisations is tedious. The automatic detection of vocalisations in recordings is explored. Important signal characteristics of elephant vocalisations were identified from spectrograms and a technique, based on the principles of existing voice activity detection algorithms, was developed to exploit these. Results obtained suggest that the algorithm can reliably detect elephant vocalisations from noisy recordings as long as the harmonic structure of vocalisations is not buried in background noise.

Automatic monitoring of pig locomotion using image analysis

“…Automatic monitoring of animals has been tested with many different species (Brendle and Hoy, 2011;Venter and Hanekom, 2010). Moreover, for farm managers this technology seems promising for monitoring purposes, mainly thanks to the broad applications automated animal monitoring has to offer.…”

Surveillance and Tracking of Elephants Using Vocal Spectral Information

“…In comparison with existing work done in [3], [4] and [5], where the authors present only elephant detection scheme and they do not discriminate elephant signal from other sound signals in the forest environment. In this work we have devised an algorithm which explores the spectral information of sound produced by animals to discriminate elephants from other animals.…”

“…In [4] G.D. De Silva andKdeZoysa, designed an infrasound recording system (hardware and software consists of a speaker (infrasound sensor) as an analog input, an amplifier, an anti-aliasing filter, an analog to digital (A/D) converter and finally a PC application which is used to analyze the recorded signal. In [5] Venter,P.J., and Hanekom,J.J proposed the possibility of using the elephant-elephant communication (elephant rumbles) to detect the presence of a herd of elephants in close proximity, In this work the authors have recorded the low frequency infrasound pattern but they do not compare with that of other animals to confirm an elephant occurrence. In the above methods audio features of elephants were used to detection.…”

An evaluation of manual and automated methods for detecting sounds of maned wolves (Chrysocyon brachyurusIlliger 1815)

“…Automated detection has been recently achieved with high success for many mammal taxa including bats (Adams et al 2010), whales (Baumgartner and Mussoline 2011) and elephants (Thompson et al 2009(Thompson et al , 2010Venter and Hanekom 2010;Zeppelzauer et al 2015). Using an automated detector can reduce the amount of labour required by rejecting portions of data that contain no target signal (Urazghildiiev and Clark 2007).…”