initial commit

+utils/shiftwrapbilinear.m

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+% out = shiftwraplinear(in,dy,dx)
+% Shifts an image with wrap around and bilinear interpolation
+
+%*-----------------------------------------------------------------------*
+%|                                                                       |
+%|  Except where otherwise noted, this work is licensed under a          |
+%|  Creative Commons Attribution-NonCommercial-ShareAlike 4.0            |
+%|  International (CC BY-NC-SA 4.0) license.                             |
+%|                                                                       |
+%|  Copyright (c) 2017 by Paul Scherrer Institute (http://www.psi.ch)    |
+%|                                                                       |
+%|       Author: CXS group, PSI                                          |
+%*-----------------------------------------------------------------------*
+% You may use this code with the following provisions:
+%
+% If the code is fully or partially redistributed, or rewritten in another
+%   computing language this notice should be included in the redistribution.
+%
+% If this code, or subfunctions or parts of it, is used for research in a 
+%   publication or if it is fully or partially rewritten for another 
+%   computing language the authors and institution should be acknowledged 
+%   in written form in the publication: “Data processing was carried out 
+%   using the “cSAXS matlab package” developed by the CXS group,
+%   Paul Scherrer Institut, Switzerland.” 
+%   Variations on the latter text can be incorporated upon discussion with 
+%   the CXS group if needed to more specifically reflect the use of the package 
+%   for the published work.
+%
+% A publication that focuses on describing features, or parameters, that
+%    are already existing in the code should be first discussed with the
+%    authors.
+%   
+% This code and subroutines are part of a continuous development, they 
+%    are provided “as they are” without guarantees or liability on part
+%    of PSI or the authors. It is the user responsibility to ensure its 
+%    proper use and the correctness of the results.
+
+function out = shiftwrapbilinear(in,dy,dx)
+
+% in = flipud(im2double(imread('cameraman.tif')));
+% in = in(1,:);
+% %in = in*0;
+% %in(100,50) = 1;
+% dy = -12;
+% dx = -500;
+
+[ny nx] = size(in);
+dyfloor = floor(dy);
+dxfloor = floor(dx);
+
+x = [1:nx]+dxfloor;
+y = [1:ny]+dyfloor;
+
+% Shift integer step (floor of desired)
+y = mod(y-1,ny)+1;
+x = mod(x-1,nx)+1;
+
+out = in(y,x);
+
+
+% Subpixel (bilinear)
+taux = dx-dxfloor;
+tauy = dy-dyfloor;
+if (taux~=0)||(tauy~=0)
+    indx    = [1:nx];
+    indxp1  = [2:nx 1]; 
+    indy    = [1:ny];
+    indyp1  = [2:ny 1];
+    out =   out(indy,indx)*(1-tauy)*(1-taux) + ...
+            out(indyp1,indx)*tauy*(1-taux) + ...
+            out(indy,indxp1)*(1-tauy)*taux + ...
+            out(indyp1,indxp1)*tauy*taux;
+end
+
+
+
+% figure(100);
+% imagesc(out);
+% axis xy equal tight;
+% colorbar
+% figure(101);
+% imagesc(real(shiftpp2(in,dy,dx)));
+% axis xy equal tight;
+% colormap gray
+% colorbar