initial commit

2026-09-17 20:39:08 +09:00 · 2026-08-07 15:56:42 +09:00
commit 91ad25aca9
1012 changed files with 159314 additions and 0 deletions
@@ -0,0 +1,119 @@
+% IMROTATE_AX_FFT fft-based image rotation for a stack of images along given axis 
+% based on "Fast Fourier method for the accurate rotation of sampled images", Optic Communications, 1997
+% img_stack = imrotate_ax_fft(img, theta, ax)
+% 
+% Inputs: 
+%   **img       - stacked array of images to be rotated 
+%   **theta     - rotation angle 
+% *optional*
+%   **axis      - rotation axis (default=3)
+% returns:
+%   ++img       - rotated image 
+
+    
+%*-----------------------------------------------------------------------*
+%|                                                                       |
+%|  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 img = imrotate_ax_fft(img, theta, axis)
+    if all(theta == 0) || isempty(img); return ; end
+
+    if nargin  < 3
+        axis = 3;
+    end
+    
+    isReal = isreal(img); 
+    
+    if axis == 1
+       img = permute(img, [3,2,1]); theta = - theta;
+    elseif axis == 2
+       img = permute(img, [1,3,2]);
+    end
+    
+    angle_90_offset = round(theta/90);
+
+    if angle_90_offset ~= 0
+        img = rot90(img, angle_90_offset); 
+        theta = theta - 90*angle_90_offset;
+    end
+    
+    if theta == 0; return ; end
+
+
+    [M, N, ~] = size(img); 
+
+    % make possible to rotate each slice with different angle 
+    theta = reshape(theta,1,1,[]) * ones(1,'like',img); % move to GPU if needed 
+    xgrid = (ifftshift(-fix(M/2):ceil(M/2)-1)'/M); 
+    ygrid = (ifftshift(-fix(N/2):ceil(N/2)-1) /N); 
+    Mgrid = (1:M)'-floor(M/2)-0.5; % the 0.5px offset is important to make the rotation equivalent to matlab imrotate
+    Ngrid = (1:N) -floor(N/2)-0.5; 
+    
+    if isa(theta, 'gpuArray')
+        [M1, M2] = arrayfun(@aux_fun, theta, xgrid, ygrid, Mgrid, Ngrid); 
+    else
+        [M1, M2] = aux_fun(theta, xgrid, ygrid, Mgrid, Ngrid); 
+    end 
+   
+    
+    % rotate images by a combination of shears 
+    img=ifft(fft(img,[],2).*M1,[],2);
+    img=ifft(fft(img,[],1).*M2,[],1);
+    img=ifft(fft(img,[],2).*M1,[],2);
+
+    if isReal
+        img = real(img); 
+    end
+
+    if axis == 1
+       img = permute(img, [3,2,1]);
+    elseif axis == 2
+       img = permute(img, [1,3,2]);
+    end
+
+  
+end
+
+% auxiliarly function to be used for GPU kernel merging
+function [M1, M2] = aux_fun(theta, xgrid, ygrid, Mgrid, Ngrid)
+
+    
+    % based on "Fast Fourier method for the accurate rotation of sampled images", Optic Communications, 1997
+    Nx = -sind(theta) .* xgrid; 
+    Ny = tand(theta/2).* ygrid;
+    
+    M1 = exp(-2i*pi*Mgrid.*Ny); 
+    M2 = exp(-2i*pi*Ngrid.*Nx); 
+
+end