Speex dev - Aug 2004 - speex_denoise on non-microphone noise (static ?)

Hi,

There seems to be some confusion as to how speex_denoise (now called
speex_preprocess) works. Unlike what some here assume, the noise
estimation is not done offline or while prompting the user. The system
automatically adapts the noise estimate when it detects that the user is
not talking. This also means that it is able to adapt to changing noise
environments - as long as the noise is not changing too fast (takes
about 1-2 seconds to adapt on average). So forget about all that
"(re-)building profile and all". All you need to do is keep calling
speex_preprocess each frame and that's all.

For those who would like to know how all this works, see "Speech
Enhancement for Non-Stationary Noise Environments"
by Cohen and Berdugo
(http://www.andreaelectronics.com/pdf_files/article.pdf )

        Jean-Marc


-- 
Jean-Marc Valin, M.Sc.A., ing. jr.
LABORIUS (http://www.gel.usherb.ca/laborius)
Université de Sherbrooke, Québec, Canada


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