%
%
% script to describe a simple binary amplitude computer generated hologram
%
% read the desired image
%
targetImage=double(imread('ima.png'));
targetImage=(1-sign(targetImage(1:512,50:700,2)-128))/2;
yscale=linspace(1,651,512);
targetImage=interp2(targetImage,yscale',(1:512));
% off set the image to separate it from the dc signal
targetImage=[zeros(512),targetImage;zeros(512),zeros(512)];
figure(1);set(gcf,'color','white');
imagesc(targetImage);axis 'square';
colormap 'gray';
% create a binary amplitude hologram by assiging transmission value 1 to
% positive phase and 0 to negative phase
hologram=(sign(angle(fftshift(fft2(targetImage))))+1)/2;
figure(2);set(gcf,'color','white');
imagesc(hologram);axis 'square';
colormap 'gray';
%
%
% The scene observed through the hologram will be the Fourier transform of
% the holographic modulation
%
reconstruction=abs(fftshift(fft2(hologram)));
reconstruction(513,513)=0;
figure(3);set(gcf,'color','white');
imagesc(reconstruction);axis 'square';
colormap 'gray';