Presentation on theme: "A Fully Automated, PC-based, Wildlife Monitoring and Survey System Neil J Boucher SoundID, Australia Michihiro Jinnai Nagoya University, Japan Biodiversity."— Presentation transcript:
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? ? ? ? ?
And they are: Parrot 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.
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).
Before and After
Spectra of the Modulation Envelope of Whale Call
Recorder for up to 2 Months of Recording
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 A GD of is a VERY dis-similar distance.
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