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From: ImageAnalyst <imageanalyst@mailinator.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: SNR and imnosie
Date: Wed, 1 Jul 2009 15:41:42 -0700 (PDT)
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On Jul 1, 3:49 pm, "Rami AbouSleiman" <rdabo...@oakland.edu> wrote:
> when i use the imnoise function as for example:
>
> I=imnoise(input, 'gaussian', 0 , 0.1)
> mean is always zero but all i vary is the variance.
> What does that mean as SNR of I?
>
> Any help is greatly appreciated.
> Thanks

---------------------------------------------------------------------------------
Well let's see.  Signal = input, and average noise = std dev = sqrt
(variance), so isn't the SNR (on average) at (x,y) just input(y, x)/
sqrt(0.1) ?     Or you can say that the actual noise = (I-input) so
then SNR(y, x) = input(y, x) / (I(y, x) - input(y,x)).

No, that can't be it, that's too obvious - you would have figured that
out - so what aren't you telling us?  If you really simply want to
know what SNR means (like you said), then you can use a nifty tool
called Google, where you might find sites like this:
http://en.wikipedia.org/wiki/Signal-to-noise_ratio