On 2016-02-16 7:55, bamerni wrote:
> Hello all,
> 
> I am trying to add noise of 5dB to an image in matlab according to the
> following steps
> 
> SNR = 5;
> Id = double(Io) / 255;
> v = var(Id(:)) / 10^(SNR/10);
> I_my_noisy = imnoise(Id, 'gaussian', 0, v);
> 
> 
> but when I measure the SNR by using the matlab command
> 
> [peaksnr,snr] = psnr(I_my_noisy, Id)
> 
> I get SNR equal 10. So, what is the wrong in my code? and why the result
> differ from my add dB?

What do you get if you use

SNR3 = 10*log10(var(Id)/var(I_my_noisy-Id))

?

What does psnr return for a simple ideal image with one single pixel "1"
(all other 0) and with the noisy image containing 2.7783 ?

Hello all,

I am trying to add noise of 5dB to an image in matlab according to the
following steps

SNR = 5;
Id = double(Io) / 255;
v = var(Id(:)) / 10^(SNR/10);
I_my_noisy = imnoise(Id, 'gaussian', 0, v);


but when I measure the SNR by using the matlab command

[peaksnr,snr] = psnr(I_my_noisy, Id)

I get SNR equal 10. So, what is the wrong in my code? and why the result
differ from my add dB?


---------------------------------------
Posted through http://www.DSPRelated.com