After inspecting your code, it seems that there are two important missing steps.
First, the roifilt2 function is working properly but the issue is in one of its inputs.
You are first computing FFT of the given input image and then scaling the dynamic range of the FFT by logarithmic function and then feeding this transformed “F_mag” to the roifilt2 function for the processing. As dynamic range of “F_mag” is already compressed, hence output of roifilt2 function i.e. filt_mask’s dynamic range will also be compressed. Hence, before feeding this into ifft2 function it is necessary to decompress its dynamic range.
You can do this by this line of code:
filt_mask = roifilt2(gaus2d, F_mag, mask);
imagesc(filt_mask);
axis image;
title('gaussian blur');
filt_mask = exp(filt_mask)-1;
Secondly, when the processed magnitude spectrum (filt_mask) and phase spectrum (Fou_phase) are combined into a single matrix “combo”, result is the shifted version of the processed FFT, as the original FFT has already been shifted at the starting of the code. Hence, here it is needed to unshift this processed FFT to get the output FFT.
You have tried to do this in the code, but you have used the wrong function. Instead of using fftshift again, use ifftshift.
img_combo2 = real(ifft2(ifftshift(combo)));
To know more details about ifftshift function, follow this link:
