Useful functions for simulations (created by LW, free to use)

[CreaPhase.git] / utilities_LW / FresnelTransform_2D.m

diff --git a/utilities_LW/FresnelTransform_2D.m b/utilities_LW/FresnelTransform_2D.m
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+## Copyright (C) 2015 Loriane Weber
+## 
+## This program is free software; you can redistribute it and/or modify
+## it under the terms of the GNU General Public License as published by
+## the Free Software Foundation; either version 3 of the License, or
+## (at your option) any later version.
+## 
+## This program is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU General Public License for more details.
+## 
+## You should have received a copy of the GNU General Public License
+## along with Octave; see the file COPYING.  If not, see
+## <http://www.gnu.org/licenses/>.
+
+## FresnelTransform
+
+## Author: Loriane Weber <lweber@hpc2-0601>
+## Created: 2015-07-01
+
+
+function Id = FresnelTransform_2D(ph, B, D, lambda, oversamp, ftot, gtot)
+
+[m, n]=size(ph);
+[m_a, n_a] = size(B);
+
+% check dimensions 
+if (m_a != m || n_a != n)
+       disp('error in the dimensions !! Phi and B should have the same dimension')
+return;
+end
+
+u = exp(-B).*exp(+i.*ph);
+    
+% propagator for the distance D
+Pd = exp(-i*pi*lambda*D*(ftot.^2+gtot.^2));  % ifftshift
+ud = ones(2*m, 2*n);
+ud(1:m,1:n) = u;
+
+ud=fft2(ud);
+
+ud = ud.*(Pd)';
+ud = ifft2(ud); 
+
+ud = ud(1:m,1:n);
+Id = abs(ud).^2;
+       
+       if oversamp==2
+               ipf = [0.25 0.5 0.25;
+                          0.50 1.0 0.50;
+                          0.25 0.5 0.25];
+               Idd = conv2(Id,ipf,'same')./conv2(ones(size(Id)),ipf,'same');
+               Idd = Idd(oversamp:oversamp:end, oversamp:oversamp:end);
+               Id=Idd;
+       elseif oversamp ==4
+   
+               ipf = [0.25 0.5 0.5 0.5 0.25;
+                          0.50 1.0 1.0 1.0 0.50;
+                          0.50 1.0 1.0 1.0 0.50;
+                          0.50 1.0 1.0 1.0 0.50;
+                          0.25 0.5 0.5 0.5 0.25];
+               Idd = conv2(Id,ipf,'same')./conv2(ones(size(Id)),ipf,'same');
+               Idd = Idd(oversamp:oversamp:end, oversamp:oversamp:end);
+               Id=Idd;
+       end % end binning detector
+        
+endfunction