## Copyright (C) 2001 Paul Kienzle ## ## 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 2 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, write to the Free Software ## Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA ## y = dct2 (x) ## Computes the 2-D discrete cosine transform of matrix x ## ## y = dct2 (x, m, n) or y = dct2 (x, [m n]) ## Computes the 2-D DCT of x after padding or trimming rows to m and ## columns to n. ## Author: Paul Kienzle ## 2001-02-08 ## * initial revision function y = dct2 (x, m, n) if (nargin < 1 || nargin > 3) usage("dct (x) or dct (x, m, n) or dct (x, [m n])"); endif if nargin == 1 [m, n] = size(x); elseif (nargin == 2) n = m(2); m = m(1); endif if m == 1 y = dct (x.', n).'; elseif n == 1 y = dct (x, m); else y = dct (dct (x, m).', n).'; endif endfunction