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41 lines
987 B
Matlab
41 lines
987 B
Matlab
function [OUT]=fresnel_propagation(IN,dxy,z,lambda)
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%FRESNEL_PROP Summary of this function goes here
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% Detailed explanation goes here
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%Parameters: dx,dy -> the pixel pitch of the object
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% z -> the distance of the propagation
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% lambda -> the wave length
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% X,Y -> meshgrid of coordinate
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% IN -> input object
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[M,N]=size(IN);
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k=2*pi/lambda;
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%coodinate grid
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lx=linspace(-dxy*M/2,dxy*M/2,M);
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[x,y]=meshgrid(lx);
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% coordinate on the output plane
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fc=1/dxy;
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fu=lambda*z*fc;
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lu=ifftshift(ifftshift(linspace(-fu/2,fu/2,M),1),2);
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[u,v]=meshgrid(lu);
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if z>0
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pf=exp(1j*k*z)*exp(1j*k*(u.^2+v.^2)/2/z);
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kern=IN.*exp(1j*k*(x.^2+y.^2)/2/z);
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kerntemp=fftshift(kern);
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cgh=fft2(kerntemp);
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OUT=fftshift(fftshift(cgh.*pf,1),2);
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else
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z=abs(z);
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pf = exp(1j*k*z)*exp(1j*k*(x.^2+y.^2)/2/z);
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cgh = ifft2(ifftshift(IN)./exp(1j*k*(u.^2+v.^2)/2/z));
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OUT = fftshift(cgh)./pf;
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end
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