Astro-ecoacoustics and a prototype detector
Acoustic detectors are widely used for the non-intrusive study of wildlife. It turns out that the data collected by these detectors have some similarities to radio astronomy data, which I’m much more familiar with. I’m interested to see how applicable some of the astronomical observation and analysis techniques are and if they can be used in eco-acoustics. Th Batto Blog describes my work to build a detector to collect and analyse audio data to try out some of these techniques as a proof of concept. I’m focusing on the use of multiple microphones (two initially) and cross-correlation of their signals to improve sensitivity and signal to noise as well as provide estimates of signal location and speed. Audio data at frequencies up 48 kHz are being recorded at present but the techniques will also work at higher frequencies..
The detector is based on a Raspberry Pi computer with a pair of digital microphones attached.
The story so far:
To summarise progress to date. Two microphones combined using a cross-correlation technique will:
allow signals about 2.7 times weaker to be detected over a single mic
increase the range of the detector by a factor of 1.6 over a single mic
provide estimates of direction to the signals, even for closely-spaced microphones with 10 to 20 deg accuracy.
More details in the Batto Blog.