function f=idtwfbreal(c,par,varargin)
%IDTWFBREAL Inverse Dual-tree Filterbank for real-valued signals
% Usage: f=idtwfbreal(c,info);
% f=idtwfbreal(c,dualwt,Ls);
%
% Input parameters:
% c : Input coefficients.
% info : Transform params. struct
% dualwt : Dual-tree Wavelet Filterbank definition
% Ls : Length of the reconstructed signal.
%
% Output parameters:
% f : Reconstructed data.
%
% f = IDTWFBREAL(c,info) reconstructs real-valued signal f from the
% coefficients c using parameters from info struct. both returned by
% DTWFBREAL function.
%
% f = IDTWFBREAL(c,dualwt,Ls) reconstructs real-valued signal f from the
% coefficients c using dual-tree filterbank defined by dualwt. Plese
% see DTWFBREAL for supported formats. The Ls parameter is mandatory
% due to the ambiguity of reconstruction lengths introduced by the
% subsampling operation.
% Note that the same flag as in the DTWFBREAL function have to be used,
% otherwise perfect reconstruction cannot be obtained. Please see help
% for DTWFBREAL for description of the flags.
%
% Examples:
% ---------
%
% A simple example showing perfect reconstruction using IDTWFBREAL:
%
% f = gspi;
% J = 7;
% wtdef = {'qshift3',J};
% c = dtwfbreal(f,wtdef);
% fhat = idtwfbreal(c,wtdef,length(f));
% % The following should give (almost) zero
% norm(f-fhat)
%
% See also: dtwfbreal dtwfbinit
%
% Url: http://ltfat.github.io/doc/wavelets/idtwfbreal.html
% Copyright (C) 2005-2023 Peter L. Soendergaard <peter@sonderport.dk> and others.
% This file is part of LTFAT version 2.6.0
%
% 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/>.
complainif_notenoughargs(nargin,2,'IDTWFBREAL');
if(~iscell(c))
error('%s: Unrecognized coefficient format.',upper(mfilename));
end
if(isstruct(par)&&isfield(par,'fname'))
complainif_toomanyargs(nargin,2,'IDTWFBREAL');
if ~strcmpi(par.fname,'dtwfbreal')
error(['%s: Wrong func name in info struct. ',...
' The info parameter was created by %s.'],...
upper(mfilename),par.fname);
end
dtw = dtwfbinit({'dual',par.wt},par.fOrder);
Ls = par.Ls;
ext = 'per';
L = wfbtlength(Ls,dtw,ext);
else
complainif_notenoughargs(nargin,3,'IDTWFBREAL');
%% PARSE INPUT
definput.keyvals.Ls=[];
definput.keyvals.dim=1;
definput.import = {'wfbtcommon'};
[flags,kv,Ls]=ltfatarghelper({'Ls'},definput,varargin);
complainif_notposint(Ls,'Ls');
ext = 'per';
% Initialize the wavelet tree structure
dtw = dtwfbinit(par,flags.forder);
[Lc,L]=wfbtclength(Ls,dtw,ext);
% Do a sanity check
if ~isequal(Lc,cellfun(@(cEl) size(cEl,1),c))
error(['%s: The coefficient subband lengths do not comply with the'...
' signal length *Ls*.'],upper(mfilename));
end
end
%% ----- step 3 : Run computation
[nodesBF, rangeLoc, rangeOut] = treeBFranges(dtw,'rev');
outLengths = nodesInLen(nodesBF,L,strcmpi(ext,'per'),dtw);
outLengths(end) = L;
f = comp_idtwfb(c,dtw.nodes(nodesBF),dtw.dualnodes(nodesBF),outLengths,...
rangeLoc,rangeOut,ext,0);
f = postpad(f,Ls);