CODEWITHSUNDEEP
matlabunwrapfringe
Sara Castillo
Sara Castillo

Reputation: 1

Wrap phase from image MATLAB

I am trying to unwrap the interference pattern that I got from the interferometre. However, the first step would be to wrap the phase, because I just got an image (intensity). I cannot post the image, but it is concentric rings with some noise. I have followed the steps from the Takeda paper, that are basically:

  1. Hanning window
  2. FFT
  3. Butterworth filter
  4. IFFT

The first problem is that the third step should be applied to the first frequency order of the FFT, but MATLAB only gives me the 0 order in the FFT.

clear all

I3=im2double(imread('Int4.bmp'));
N=1024;
w=hann(N);          % hanning window 
m1 = w(:)*w(:).' ;  %' Create 2D window 
I1=I3(:,129:1152).*m1; 
D = fftshift(fft2(fftshift(I1)));%,2048,2048)); 

% Create Butterworth filter: 
nx=512; ny=512; d1=10; 
fftI=D(1:1023,1:1023); 
n=2; 
filter3 = ones(2*nx-1,2*ny-1); 

for i = 1:2*nx-1 
    for j =1:2*ny-1 
        dist = ((i-(nx+1))^2 + (j-(ny+1))^2)^.5; 
        filter3(i,j) = (1/(1 + (dist/d1)^(2*n))).*filter3(i,j); 
    end
end

% Update image with passed frequencies. 
filtered_image = ifftshift(ifft2(ifftshift(filter3.*fftI),N-1,N-1)) ;

I would appreciate any suggestion or comments.

Thank you very much!!

Upvotes: 0

Views: 745

Answers (0)

Related Questions