Subject: Re: [linux-audio-dev] idea: wavelets of variable frequencies
From: Fons Adriaensen (fons.adriaensen_AT_skynet.be)
Date: Fri Jun 20 2003 - 01:24:55 EEST
On Thu, Jun 19, 2003 at 11:23:07PM +0200, Tom Weber wrote:
!
> Instead of doing a discrete fourier transform when reading a small
> frame of the sound, do a dense transform (every 0.1 Hz?) and pick out
> the peaks. Then assume that a similar enough frequency in the next
> frame comes from the same source, keep joining those and your sound
> will be represented by a lot of oscillators (wavelets) with amplitude
> and frequency curves. I guess this would overcome the weaknesses in
> having fixed frequencies.
There may be some problems...
- What about noise-like signals ?
- For a resolution of 0.1 Hz you need 10 seconds of sound. Only a real
sine wave lasting the whole 10 s will tranform as a 'peak', everything
else will be smeared out.
The normal way to use wavelets is to make them shorter at high frequencies,
sort of DFT with a log frequency scale.
> This idea shouldn't be new, where can I read about it? Has it been
> implemented anywhere?
There are lots of resources on wavelets on the web. Ask google.
-- FA
This archive was generated by hypermail 2b28 : Fri Jun 20 2003 - 01:51:23 EEST