imdct2.m

Matlab时频分析工具箱,希望能对大家有所帮助啊

function [f]=imdct2(c,g1,p3,p4)
%IMDCT2  2D Inverse Discrete Wilson transform.
%   Usage: f=imdct2(c,g);
%          f=imdct2(c,g1,g2);
%          f=imdct2(c,g1,g2,Ls);
%
%   Input parameters:
%         c       : Array of coefficients.
%         g,g1,g2 : Window functions.
%         Ls      : Size of reconstructed signal.
%   Output parameters:
%         f       : Output data, matrix.
%
%   IMDCT2(c,g) will calculate a separable two dimensional inverse
%   MDCT transformation of the input coefficients c using the
%   window g. The number of channels is deduced from the size of the
%   coefficients c.
%
%   IMDCT2(c,g1,g2) will do the same using the window g1 along the first
%   dimension, and window g2 the second dimension.
%
%   IMDCT2(c,g1,g2,Ls) will cut the signal to size Ls after the
%   transformation is done.
%
%   SEE ALSO:  MDCT2, DGT2, WILDUAL

% 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/>.

%   Author : Peter Soendergaard

error(nargchk(2,4,nargin));

doLs=0;

switch nargin
  case 2
    g2=g1;
  case 3
    if prod(size(p3))>2
      % Two windows was specified.
      g2=p3;
    else
      g2=g1;
      Ls=p3;
      doLs=1;
    end;
  case 4
    g2=p3;
    Ls=p4;
    doLs=1;
end;
  
if size(g1,2)>1
  if size(g1,1)>1
    error('g1 must be a vector');
  else
    % g1 was a row vector.
    g1=g1(:);
  end;
end;

if size(g2,2)>1
  if size(g2,1)>1
    error('g2 must be a vector');
  else
    % g2 was a row vector.
    g2=g2(:);
  end;
end;

Lwindow1=size(g1,1);
Lwindow2=size(g2,1);

if ndims(c)<4 || ndims(c)>5
  error('c must be 4 or 5 dimensional.');
end;

M1=size(c,1);
N1=size(c,2);
M2=size(c,3);
N2=size(c,4);
W=size(c,5);

a1=M1;
a2=M2;

L1=a1*N1;
L2=a2*N2;

% Length of window must be dividable by M.
% We cannot automically zero-extend the window, as it can
% possible break some symmetry properties of the window, and we don't
% know which symmetries to preserve.
if rem(Lwindow1,M1)~=0
  error('Length of window no. 1 must be dividable by M1.')
end;

if rem(Lwindow2,M2)~=0
  error('Length of window no. 2 must be dividable by M2.')
end;

% If input is real, and window is real, output must be real as well.
inputwasreal = (isreal(g1) && isreal(g2) && isreal(c));


% --- first dimension

% Change c to correct shape.
c=reshape(c,M1*N1,L2*W);

c=comp_igdgt(comp_idwiltiii(c,a1,M1),g1,a1,2*M1,L1,0,.5,0,0);

% Check if Ls was specified.
if doLs
  c=postpad(c,Ls(1));
else
  Ls(1)=L1;
end;

% Change to correct size
c=reshape(c,Ls(1),L2,W);

% Exchange first and second dimension.
c=permute(c,[2,1,3]);

% --- second dimension

% Change c to correct shape.
c=reshape(c,M2*N2,Ls(1)*W);

c=comp_igdgt(comp_idwiltiii(c,a2,M2),g2,a2,2*M2,L2,0,.5,0,0);

% Check if Ls was specified.
if doLs
  c=postpad(c,Ls(2));
else
  Ls(2)=L2;
end;

% Change to correct size
c=reshape(c,Ls(2),Ls(1),W);

% Exchange first and second dimension.
f=permute(c,[2,1,3]);

% Clean signal if it is known to be real
if inputwasreal
  f=real(f);
end;