CETACEAN ACOUSTICS: HOW TO DO WHALES AND WAVELETS
If you want to know the science, you kind of need to begin with basic Calculus and introductory physics, especially the physics of waves. For a good online introduction to acoustics in the ocean, check out Acoustic Ecology's page here.
Second, to explore the world of cetacean sound, it helps to understand the physics of sound in the ocean. There are significant differences between sound in the ocean and the sounds we hear in the air. For example, the ocean conducts sound at 5 times the speed it travels in air, and has a beautiful 'lensing' property that is a function of depth and temperature [specifically, sound travels faster at the top and bottom of the ocean, slower in the middle], thus creating what is known as the 'deep sound channel'. To study up on these things I would recommend "Marine Mammals and Noise" as a good place to start. From ATOC and HIFT (also described in MM&N) we know that a sound as loud as a Blue whale makes can span half the world's oceans, which means two (well, probably three as noisy as the oceans are today ) whales could send a signal around the globe in just over 7 hours. Like, you know, if they wanted to.
Third, you have to consider the science of wavelets. My best recommendation for a place to start is Ms. Amara Graps' page, here.
To actually perform the analysis you need to know a little programming. This could be done in C/C++, or you could use a variety of mathematical software tools, such as Mathematica or Matlab.
So, what we do is to take a sound clip, transform it using wavelets, then display the product of this operation using some algorithm that maps the resulting matrix to a range of colors to make a kind of 'paint by numbers' picture; exactly as children would fill in a coloring book. What you are seeing is a picture of how well a particular sound correlates to a particular base function- that is, how much one shape looks like another. That's kind of all there is to it.
Mark Fischer (USA) is a cetacean acoustics specialist. 1961 born, Pittsburgh, Pennsylvania.
1979-1983 US Army, stationed in Amberg, Germany;
1983-1987 Earned BS in electronics and computer engineering from George Mason University
1988-1998 Software development in defense and telecommunications
1999-2002 Walkabout, Baja California
Since then - independent research in cetacean acoustics using wavelets, exploring both the science and the art of the way they use sound.
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