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that a low-cost microphone can be used for insect-
detection purposes. This is so because in case of high-
level background noise, even if it is white, as it has
been proved, ICA is capable of extracting the burst
of impulses. This means that accelerometers-based
equipment could be displaced when it is not needed a
high sensitive device. In the case of a high sensibil-
ity requirement, accelerometers can be used to extract
distorted information which would be ICA processed
to extract the possible vibratory signals produced by
insects.
Finally, we attend the bandwidth specification of
the AE sensor. Traditional methods compare the im-
pulsive response of the AE sensor with the spec-
trum of the acquired signal, based on the hypothe-
sis that bursts produced by termites comprise straight
pulses (Robbins et al., 1991). In the case of an
ICA method of detection no frequency-domain com-
parison is needed; a time-domain characterization is
enough.
Further experiments will be developed in residen-
tial zones where background noise is high and where
coloured noise is present. This would be the next step
in checking the performance.
ACKNOWLEDGMENT
The authors would like to thank the Spanish Ministry
of Science and Technology for funding the project
DPI2003-00878, and the Andalusian Autonomous
Government Division for funding the research with
Contraplagas Ambiental S.L.
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