/usr/share/octave/site/m/vlfeat/toolbox/imop/vl_imwbackward.m is in octave-vlfeat 0.9.17+dfsg0-6build1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 | function [wI,wIx,wIy] = vl_imwbackward(varargin)
% VL_IMWBACKWARD Image backward warping
% J = VL_IMWBACKWARD(I, X, Y) returns the values of image I at
% locations X,Y. X and Y are real matrices of arbitrary but
% identical dimensions. I is bilinearly interpolated between samples
% and extended with NaNs to the whole real plane.
%
% [J,JX,JY] = VL_IMWBACKWARD(...) returns the warped derivatives JX and
% JY too.
%
% By default, VL_IMWBACKWARD() assumes that the image I uses the standard
% coordinate system. VL_IMWBACKWARD(XR,YR,I,X,Y) assumes instead that I
% is defined on a rectangular grid specified by the vectors XR and
% YR.
%
% VL_IMWBACKWARD() is less general than the MATLAB native function
% INTERP2(), but it is significantly faster.
%
% See also: IMWFORWARD(), INTERP2(), VL_HELP().
% Copyright (C) 2007-12 Andrea Vedaldi and Brian Fulkerson.
% All rights reserved.
%
% This file is part of the VLFeat library and is made available under
% the terms of the BSD license (see the COPYING file).
if nargin < 5
I = varargin{1} ;
[M,N,K] = size(I) ;
xr = 1:N ;
yr = 1:M ;
varargin = { varargin{2:end} } ;
else
xr = varargin{1} ;
yr = varargin{2} ;
I = varargin{3} ;
[M,N,K] = size(I) ;
varargin = { varargin{4:end} } ;
end
if K == 1
if nargout == 1
wI = vl_imwbackwardmx(xr, yr, I, varargin{:}) ;
else
[wI,wIx,wIy] = vl_imwbackwardmx(xr, yr, I, varargin{:}) ;
end
else
[M,N] = size(varargin{1}) ;
if nargout == 1
wI = zeros(M,N,K) ;
for k=1:K
wI(:,:,k) = vl_imwbackwardmx(xr, yr, squeeze(I(:,:,k)), varargin{:}) ;
end
else
wI = zeros(M,N,K) ;
wIx = zeros(M,N,K) ;
wIy = zeros(M,N,K) ;
for k=1:K
[tmp1, tmp2, tmp3] = vl_imwbackwardmx(xr, yr, squeeze(I(:,:,k)), varargin{:}) ;
wI(:,:,k) = tmp1;
wIx(:,:,k) = tmp2;
wIy(:,:,k) = tmp3 ;
end
end
end
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