7017
|
1 ## Copyright (C) 2001, 2006, 2007 Paul Kienzle |
5820
|
2 ## |
|
3 ## This file is part of Octave. |
|
4 ## |
|
5 ## Octave is free software; you can redistribute it and/or modify it |
|
6 ## under the terms of the GNU General Public License as published by |
7016
|
7 ## the Free Software Foundation; either version 3 of the License, or (at |
|
8 ## your option) any later version. |
5820
|
9 ## |
|
10 ## Octave is distributed in the hope that it will be useful, but |
|
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
|
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
|
13 ## General Public License for more details. |
|
14 ## |
|
15 ## You should have received a copy of the GNU General Public License |
7016
|
16 ## along with Octave; see the file COPYING. If not, see |
|
17 ## <http://www.gnu.org/licenses/>. |
5820
|
18 |
5996
|
19 ## -*- texinfo -*- |
6575
|
20 ## @deftypefn {Function File} {@var{y} =} filter2 (@var{b}, @var{x}) |
6549
|
21 ## @deftypefnx {Function File} {@var{y} =} filter2 (@var{b}, @var{x}, @var{shape}) |
5820
|
22 ## Apply the 2-D FIR filter @var{b} to @var{x}. If the argument |
|
23 ## @var{shape} is specified, return an array of the desired shape. |
5997
|
24 ## Possible values are: |
5820
|
25 ## |
|
26 ## @table @asis |
|
27 ## @item 'full' |
|
28 ## pad @var{x} with zeros on all sides before filtering. |
|
29 ## @item 'same' |
|
30 ## unpadded @var{x} (default) |
|
31 ## @item 'valid' |
|
32 ## trim @var{x} after filtering so edge effects are no included. |
|
33 ## @end table |
|
34 ## |
|
35 ## Note this is just a variation on convolution, with the parameters |
|
36 ## reversed and @var{b} rotated 180 degrees. |
|
37 ## @seealso{conv2} |
5996
|
38 ## @end deftypefn |
5820
|
39 |
|
40 ## Author: Paul Kienzle <pkienzle@users.sf.net> |
|
41 ## 2001-02-08 |
|
42 ## * initial release |
|
43 |
|
44 function Y = filter2 (B, X, shape) |
|
45 |
|
46 if (nargin < 2 || nargin > 3) |
6046
|
47 print_usage (); |
5820
|
48 endif |
|
49 if (nargin < 3) |
|
50 shape = "same"; |
|
51 endif |
|
52 |
|
53 [nr, nc] = size(B); |
|
54 Y = conv2 (X, B(nr:-1:1, nc:-1:1), shape); |
|
55 endfunction |