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scripts/signal/filter2.m

changeset 10289: 4b124317dc38
parent:1bf0ce0930be
author: John W. Eaton <jwe@octave.org>
date: Tue Feb 09 20:58:55 2010 -0500 (64 minutes ago)
permissions: -rw-r--r--
description: base_properties::set_children: account for hidden children 
     1## Copyright (C) 2001, 2006, 2007, 2009 Paul Kienzle

     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

     7## the Free Software Foundation; either version 3 of the License, or (at

     8## your option) any later version.

     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

    16## along with Octave; see the file COPYING.  If not, see

    17## <http://www.gnu.org/licenses/>.

    18

    19## -*- texinfo -*-

    20## @deftypefn {Function File} {@var{y} =} filter2 (@var{b}, @var{x})

    21## @deftypefnx {Function File} {@var{y} =} filter2 (@var{b}, @var{x}, @var{shape})

    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.

    24## Possible values are: 

    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}

    38## @end deftypefn

    39

    40## Author: Paul Kienzle <pkienzle@users.sf.net>

    41## 2001-02-08 

    42##    * initial release

    43

    44function Y = filter2 (B, X, shape)

    45

    46  if (nargin < 2 || nargin > 3)

    47    print_usage ();

    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);

    55endfunction