Add a useful package (from Source forge) for octave

[CreaPhase.git] / octave_packages / signal-1.1.3 / idct2.m

diff --git a/octave_packages/signal-1.1.3/idct2.m b/octave_packages/signal-1.1.3/idct2.m
new file mode 100644 (file)
index 0000000..a9caba7
--- /dev/null
+++ b/octave_packages/signal-1.1.3/idct2.m
@@ -0,0 +1,44 @@
+## Copyright (C) 2001 Paul Kienzle <pkienzle@users.sf.net>
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 3 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+## FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, see <http://www.gnu.org/licenses/>.
+
+## y = idct2 (x)
+##   Computes the inverse 2-D discrete cosine transform of matrix x
+##
+## y = idct2 (x, m, n) or y = idct2 (x, [m n])
+##   Computes the 2-D inverse DCT of x after padding or trimming rows to m and
+##   columns to n.
+
+function y = idct2 (x, m, n)
+
+  if (nargin < 1 || nargin > 3)
+    print_usage;
+  endif
+
+  if nargin == 1
+    [m, n] = size (x);
+  elseif (nargin == 2)
+    n = m (2);
+    m = m (1);
+  endif
+
+  if m == 1
+    y = idct (x.', n).';
+  elseif n == 1
+    y = idct (x, m);
+  else
+    y = idct (idct (x, m).', n).';
+  endif
+
+endfunction