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Asked by vipul utsav
on 29 Dec 2012

one person say me that actual snr is,,,

if noiseImage=noisyImage-originalImage then actual snr=mean(originalImage./abs(noiseImage)) so my question is that "Is snr depends on mean and variance of noiseImage"?

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Answer by Image Analyst
on 29 Dec 2012

Yes. More noise = lower SNR, and less noise = higher SNR.

Walter Roberson
on 29 Dec 2012

Considering that the mean is being taken, does the *variance* of noiseImage affect the SNR? I don't see how: I just see how the *mean* affects the SNR.

Image Analyst
on 29 Dec 2012

Because the absolute value of the noise image is being taken, the std dev affects the mean. You could have a mean of zero in the original noise, but once you take the abs(), now the mean depends on the std dev. So the SNR of an image with noise = 0 +/- 5 gray levels will be higher than the SNR of the same image with a noise of 0 +/- 200 gray levels.

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