How to deconvolve an image in MATLAB? i was using weiner filter for this purpose but didn't get the results.

6 views (last 30 days)
Shoaib Ul Hassan
Shoaib Ul Hassan on 2 Mar 2020
Commented: Gab D on 6 Aug 2020
function ex = wienerFilter(y,h,sigma,gamma,alpha);
%
% ex = wienerFilter(y,h,sigma,gamma,alpha);
%
% Generalized Wiener filter using parameter alpha. When
% alpha = 1, it is the Wiener filter. It is also called
% Regularized inverse filter.
%
% Reference: Richb's paper
% Created: Tue May 4 16:24:06 CDT 1999, Huipin Zhang
N = size(y,1);
Yf = fft2(y);
Hf = fft2(h,N,N);
Pyf = abs(Yf).^2/N^2;
% direct implementation of the regularized inverse filter,
% when alpha = 1, it is the Wiener filter
% Gf = conj(Hf).*Pxf./(abs(Hf.^2).*Pxf+alpha*sigma^2);
%
% Since we don't know Pxf, the following
% handle singular case (zero case)
sHf = Hf.*(abs(Hf)>0)+1/gamma*(abs(Hf)==0);
iHf = 1./sHf;
iHf = iHf.*(abs(Hf)*gamma>1)+gamma*abs(sHf).*iHf.*(abs(sHf)*gamma<=1);
Pyf = Pyf.*(Pyf>sigma^2)+sigma^2*(Pyf<=sigma^2);
Gf = iHf.*(Pyf-sigma^2)./(Pyf-(1-alpha)*sigma^2);
% max(max(abs(Gf).^2)) % should be equal to gamma^2
% Restorated image without denoising
eXf = Gf.*Yf;
ex = real(ifft2(eXf));
return
  1 Comment
Gab D
Gab D on 6 Aug 2020
Hi, could you provide de full reference of Richb's paper? I am not able to determine what is the gamma variable.
Also, since we dont know Pxf, could we just use an approximation based on a standart Fourier deconvolution X_0hat=Y/H and compute Pxf from there?
Thank you in advance for your help!

Sign in to comment.

Answers (1)

Daniel Vieira
Daniel Vieira on 2 Mar 2020
Looking superficially this code seems right, would have to go through the theory to check. But you can also use the function wiener2.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!