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image: new spatial transformation functions * maketform: accept input/output control points as second and third argument * imtransform: new function * findsbounds: new function * private/istform: add comment on what function does * NEWS/INDEX: update list of new functions
author carandraug
date Sun, 28 Apr 2013 02:31:13 +0000
parents bb7e5991924f
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745:27d87f06dd99 746:43686e9e8eae
1 ## Copyright (C) 2012 Pantxo Diribarne 1 ## Copyright (C) 2012 Pantxo Diribarne
2 ## 2 ##
3 ## This program is free software; you can redistribute it and/or modify 3 ## This program is free software; you can redistribute it and/or modify
4 ## it under the terms of the GNU General Public License as published by 4 ## it under the terms of the GNU General Public License as published by
5 ## the Free Software Foundation; either version 3 of the License, or 5 ## the Free Software Foundation; either version 3 of the License, or
6 ## (at your option) any later version. 6 ## (at your option) any later version.
7 ## 7 ##
8 ## This program is distributed in the hope that it will be useful, 8 ## This program is distributed in the hope that it will be useful,
9 ## but WITHOUT ANY WARRANTY; without even the implied warranty of 9 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 10 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 ## GNU General Public License for more details. 11 ## GNU General Public License for more details.
12 ## 12 ##
13 ## You should have received a copy of the GNU General Public License 13 ## You should have received a copy of the GNU General Public License
14 ## along with Octave; see the file COPYING. If not, see 14 ## along with Octave; see the file COPYING. If not, see
15 ## <http://www.gnu.org/licenses/>. 15 ## <http://www.gnu.org/licenses/>.
16 16
17 ## -*- texinfo -*- 17 ## -*- texinfo -*-
18 ## @deftypefn {Function File} {@var{T} =} maketform (@var{ttype}, @var{tmat}) 18 ## @deftypefn {Function File} {@var{T} =} maketform (@var{ttype}, @var{tmat})
19 ## @deftypefnx {Function File} {@var{T} =} maketform (@var{ttype}, @var{inc}, @var{outc})
19 ## @deftypefnx {Function File} {@var{T} =} maketform ("custom", @var{ndims_in}, @var{ndims_out}, @var{forward_fcn}, @var{inverse_fcn}, @var{tdata}) 20 ## @deftypefnx {Function File} {@var{T} =} maketform ("custom", @var{ndims_in}, @var{ndims_out}, @var{forward_fcn}, @var{inverse_fcn}, @var{tdata})
21 ## Create structure for spatial transformations.
22 ##
20 ## Returns a transform structure containing fields @var{ndims_in}, 23 ## Returns a transform structure containing fields @var{ndims_in},
21 ## @var{ndims_out}, @var{forward_fcn}, @var{inverse_fcn} and @var{tdata}. The content 24 ## @var{ndims_out}, @var{forward_fcn}, @var{inverse_fcn} and @var{tdata}. The
22 ## of each field depends on the requested transform type @var{ttype}: 25 ## content of each field depends on the requested transform type @var{ttype}:
26 ##
23 ## @table @asis 27 ## @table @asis
24 ## @item "projective" 28 ## @item "projective"
25 ## A ndims_in = N -> ndims_out = N projective transformation structure 29 ## A ndims_in = N -> @var{ndims_out} = N projective transformation structure
26 ## is returned. 30 ## is returned.
27 ## The second input argument @var{tmat} must be a (N+1)-by-(N+1) 31 ## The second input argument @var{tmat} must be a (N+1)-by-(N+1)
28 ## transformation matrix. The 32 ## transformation matrix. The
29 ## (N+1)th column must contain projection coefficients. As an example a two 33 ## (N+1)th column must contain projection coefficients. As an example a two
30 ## dimentionnal transform from [x y] coordinates to [u v] coordinates 34 ## dimentionnal transform from [x y] coordinates to [u v] coordinates
31 ## is represented by a transformation matrix defined so that: 35 ## is represented by a transformation matrix defined so that:
36 ##
32 ## @example 37 ## @example
33 ## [xx yy zz] = [u v 1] * [a d g; 38 ## [xx yy zz] = [u v 1] * [a d g;
34 ## b e h; 39 ## b e h;
35 ## c f i] 40 ## c f i]
36 ## [x y] = [xx./zz yy./zz]; 41 ## [x y] = [xx./zz yy./zz];
37 ## @end example 42 ## @end example
43 ##
44 ## Alternatively the transform can be specified using a quadilateral
45 ## coordinates (typically the 4 corners of the
46 ## image) in the input space (@var{inc}, 4-by-ndims_in matrix) and in
47 ## the output space (@var{outc}, 4-by-ndims_out matrix). This is
48 ## equivalent to building the transform using
49 ## @code{T = cp2tform (@var{inc}, @var{outc}, "projective")}.
50 ##
38 ## @item "affine" 51 ## @item "affine"
39 ## Affine is a subset of projective transform (see above). A ndims_in = N -> 52 ## Affine is a subset of projective transform (see above). A
40 ## ndims_out = N affine transformation structure is returned. 53 ## @var{ndims_in} = N -> @var{ndims_out} = N affine transformation structure is
54 ## returned.
41 ## The second input argument @var{tmat} must be a (N+1)-by-(N+1) or 55 ## The second input argument @var{tmat} must be a (N+1)-by-(N+1) or
42 ## (N+1)-by-(N) transformation matrix. If present, the (N+1)th column must 56 ## (N+1)-by-(N) transformation matrix. If present, the (N+1)th column must
43 ## contain [zeros(N,1); 1] so that projection is suppressed. 57 ## contain [zeros(N,1); 1] so that projection is suppressed.
58 ##
59 ## Alternatively the transform can be specified a using a triangle
60 ## coordinates (typically the 3 corners of the
61 ## image) in the input space (@var{inc}, 3-by-ndims_in matrix) and in
62 ## the output space (@var{outc}, 3-by-ndims_out matrix). This is
63 ## equivalent to building the transform using "T = cp2tform (@var{inc}, @var{outc},
64 ## 'affine')".
65 ##
44 ## @item "custom" 66 ## @item "custom"
45 ## For user defined transforms every field of the transform structure 67 ## For user defined transforms every field of the transform structure
46 ## must be supplied. The prototype of the transform functions, 68 ## must be supplied. The prototype of the transform functions,
47 ## @var{forward_fcn} and @var{inverse_fcn}, should be X' = 69 ## @var{forward_fcn} and @var{inverse_fcn}, should be X' =
48 ## transform_fcn (X, T). X and X' are respectively p-by-ndims_in and 70 ## transform_fcn (X, T). X and X' are respectively p-by-ndims_in and
49 ## p-by-ndims_out arrays for forward_fcn and reversed for inverse_fcn. 71 ## p-by-ndims_out arrays for forward_fcn and reversed for inverse_fcn.
50 ## The argument T is the transformation structure which will contain 72 ## The argument T is the transformation structure which will contain
51 ## the user supplied transformation matrix @var{tdata}. 73 ## the user supplied transformation matrix @var{tdata}.
52 ## @end table 74 ## @end table
75 ##
53 ## @seealso{tformfwd, tforminv, cp2tform} 76 ## @seealso{tformfwd, tforminv, cp2tform}
54 ## @end deftypefn 77 ## @end deftypefn
55 78
56 ## Author: Pantxo Diribarne <pantxo@dibona> 79 ## Author: Pantxo Diribarne <pantxo@dibona>
57 ## Created: 2012-09-05
58 80
59 function T = maketform (ttype, varargin) 81 function T = maketform (ttype, varargin)
60 82
61 if (nargin < 2 || ! any (strcmp (ttype, {"affine", "projective", "custom"}))) 83 if (nargin < 2 || ! any (strcmpi (ttype, {"affine", "projective", "custom"})))
62 print_usage (); 84 print_usage ();
63 endif 85 endif
86
64 if (numel (varargin) == 1) 87 if (numel (varargin) == 1)
65 tmat = varargin {1}; 88 tmat = varargin {1};
66 ndin = rows (tmat) - 1; 89 ndin = rows (tmat) - 1;
67 ndout = columns (tmat) - 1; 90 ndout = columns (tmat) - 1;
68 if (ndin < 2); 91 if (ndin < 2);
92 T.ndims_out = ndout; 115 T.ndims_out = ndout;
93 T.forward_fcn = forward_fcn; 116 T.forward_fcn = forward_fcn;
94 T.inverse_fcn = inverse_fcn; 117 T.inverse_fcn = inverse_fcn;
95 T.tdata.T = tmat; 118 T.tdata.T = tmat;
96 T.tdata.Tinv = inv (tmat); 119 T.tdata.Tinv = inv (tmat);
120
121 elseif (numel (varargin) == 2)
122 inc = varargin{1};
123 outc = varargin{2};
124 if (strcmp (ttype, "affine"))
125 if (all (size (inc) == size (outc)) &&
126 all (size (inc) == [3 2]))
127 T = cp2tform (inc, outc, ttype);
128 else
129 error ("maketform: expect INC and OUTC to be 3-by-2 vectors.");
130 endif
131 elseif (strcmp (ttype, "projective"))
132 if (all (size (inc) == size (outc)) &&
133 all (size (inc) == [4 2]))
134 T = cp2tform (inc, outc, ttype);
135 else
136 error ("maketform: expect INC and OUTC to be 4-by-2 vectors.");
137 endif
138 endif
139
97 elseif (numel (varargin) == 5 && strcmpi (ttype, "custom")) 140 elseif (numel (varargin) == 5 && strcmpi (ttype, "custom"))
98 if (isscalar (varargin{1}) && isscalar (varargin{2}) 141 if (isscalar (varargin{1}) && isscalar (varargin{2})
99 && varargin{1} > 0 && varargin{2} > 0) 142 && varargin{1} > 0 && varargin{2} > 0)
100 T.ndims_in = varargin{1}; 143 T.ndims_in = varargin{1};
101 T.ndims_out = varargin{2}; 144 T.ndims_out = varargin{2};
112 else 155 else
113 error ("maketform: expect function handle as inverse_fcn.") 156 error ("maketform: expect function handle as inverse_fcn.")
114 endif 157 endif
115 158
116 T.tdata = varargin{5}; 159 T.tdata = varargin{5};
160
117 else 161 else
118 print_usage (); 162 print_usage ();
119 endif 163 endif
120 endfunction 164 endfunction
121 165