A Fully Automated, PC-based, Wildlife Monitoring and Survey

System

Neil J Boucher

SoundID, Australia

Michihiro Jinnai

Nagoya University, Japan

Biodiversity Technologies Symposium

Oxford

September 2012

What are these Calls?

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?

?

?

And they are:

Parrot

Humpback Whale

Humpback Whale

Mydau Bat

Harmonics

• In the real world, harmonics are mostly generated by distortion.

• In engineering we take great pains to avoid them.

• Harmonics have few uses (outside of music) and are mostly undesirable.

Harmonics in Bio-Acoustics

• These are mostly artefacts of the FFT (also known as the Harmonic Transform).

• They are sometimes the result of faulty/poor quality recording equipment.

• Occasionally animals actually produce harmonics.

Harmonics?

Why waste Energy?

• Were the whale to actually generate all those harmonics (with high frequencies and high propagation losses), it would be a very inefficient way to communicate.

• Additionally the sound of the whale would vary noticeably with distance (less high frequencies at distance).

Modulation

Before and After

Spectra of the Modulation Envelope of Whale Call

Recorder for up to 2 Months of Recording

Long-term Recorders

The Software

References

• The system works by comparing a library of WAV files (stored as mathematical images of their LPC spectrogram) with the spectrograms of the target sound.

LPC Transform Image of Kookaburra

LPC Transform of Rosella

Compare the Patterns as Images

Measure the Similarity using GD (here GD=10.80)

Geometric Distance

• It is an angle between two vectors (measured in degrees).

• For field recordings a distance of 6 degrees or less implies similarity of the sounds.

• Concept was developed by Jinnai.

• It measures the similarity of two sounds!

Determine a Similarity Value (GD)

• Typically we would use GD<=6.00 for similar matching call types.

• GD is “sort of” logarithmic, so calls with a GD of 6.00 are “roughly” 10 x more similar than those with a GD of 7.00.

• A GD of 10. 80 is a VERY dis-similar distance.

Dawn Chorus List• Australian Crow (Corvus spp.)• Pied Currawong (Strepera graculina)• Eastern Whipbird (Psophodes olvaceus)• Grey Shrike-thrush (Colluricincla harmonica)• Guineafowl (Numida spp.)• Kookaburra (Dacelo spp.)• Lewin’s Honeyeater (Meliphaga lewinii)• Magpie (Gymnorhina tibicen)• Noisy Miner (Manorina melanocephala)• Pale-headed Rosella (Platycercus adscitus)• Pied Butcherbird (Cracticus nigrogularis)• Spur-winged Plover (Vanellus spp.)• Rainbow Lorikeet (Trichoglossus haematodus)• Eastern Sedgefrog (Litoria fallax)

Results from 1 Hour and 8 minutes of Dawn Chorus

Capabilities

• >100,000 comparisons per second

• Can analyse a whole HDD in a single run

• Can have any number of different species being searched for at the same time

• Accuracy greater than human expert

• Real-time recognition is possible

• Can handle terabytes of data in batch mode

PC Specs

• Any Windows PC will run the software

• Ideally one with a fast clock (>2.5 GHz)

• Screen size 1920 x 1080 is best

Time and Frequency Domain Image

Conclusions

• The time of the “better than human” sound identification has come.

• Very large acoustic surveys are now possible.

• The package has lots of new analysis tools.

• The system is available now at www.soundid.net