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function f = ifwt2(c,w,J,varargin)
%-*- texinfo -*-
%@deftypefn {Function} ifwt2
%@verbatim
%IFWT2 Inverse Fast Wavelet Transform
% Usage: f = ifwt2(c,w,J)
% f = ifwt2(c,w,J,Ls,...)
%
% Input parameters:
% c : Coefficients stored in a matrix.
% w : Wavelet filters definition.
% J : Number of filterbank iterations.
% Ls : Size of the reconstructed signal.
%
% Output parameters:
% f : Reconstructed data.
%
% f = IFWT2(c,w,J) reconstructs signal f from the wavelet coefficients
% c using a J*-iteration synthesis filterbank build from the basic
% synthesis filterbank defined by w. f is a matrix with
% size(f)==size(c).
%
% f = IFWT2(c,w,J,Ls) works as above but the result f is cut or
% extended to size Ls if Ls is a two-element vector or to [Ls,Ls]
% if Ls is a scalar.
%
% This function takes the same optional parameters as FWT2. Please see
% the help on FWT2 for a description of the parameters.
%
%
%
% References:
% S. Mallat. A wavelet tour of signal processing. Academic Press, San
% Diego, CA, 1998.
%
%
%@end verbatim
%@strong{Url}: @url{http://ltfat.github.io/doc/wavelets/ifwt2.html}
%@seealso{fwt2, fwtinit, demo_imagecompression}
%@end deftypefn
% Copyright (C) 2005-2016 Peter L. Soendergaard <peter@sonderport.dk>.
% This file is part of LTFAT version 2.3.1
%
% 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: Zdenek Prusa
if nargin<3
error('%s: Too few input parameters.',upper(mfilename));
end;
if ~isnumeric(c)
error('%s: Unrecognized coefficient format.',upper(mfilename));
end;
% Initialize the wavelet filters structure
w = fwtinit(w);
%% PARSE INPUT
definput.keyvals.Ls=[];
definput.import = {'fwt','fwt2'};
[flags,kv,Ls]=ltfatarghelper({'Ls'},definput,varargin);
if (isempty(Ls))
Ls = size(c);
end
if (numel(Ls)==1)
Ls = [Ls,Ls];
end
Lcrows = fwtclength(Ls(1),w,J,'per');
Lccols = fwtclength(Ls(2),w,J,'per');
nFilts = numel(w.g);
if flags.do_standard
Jstep = 1;
for jj=1:J-1
LcIdx = jj*(nFilts-1)+2;
colRange = 1:Lcrows(LcIdx);
rowRange = 1:Lccols(LcIdx);
c(colRange,rowRange) = ifwt(c(colRange,rowRange),w,Jstep,Lcrows(LcIdx),'dim',1,'per');
c(colRange,rowRange) = ifwt(c(colRange,rowRange),w,Jstep,Lccols(LcIdx),'dim',2,'per');
end
c = ifwt(c,w,Jstep,Ls(1),'dim',1,'per');
f = ifwt(c,w,Jstep,Ls(2),'dim',2,'per');
end;
if flags.do_tensor
f = ifwt(c,w,J,Ls(1),'dim',1,'per');
f = ifwt(f,w,J,Ls(2),'dim',2,'per');
end;
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