function y = idualtree(w, J, Fsf, sf)

% Inverse Dual-tree Complex DWT
%
% USAGE:
%    y = idualtree(w, J, Fsf, sf)
% INPUT:
%    w - DWT coefficients
%    J - number of stages
%    Fsf - synthesis filters for the last stage
%    sf - synthesis filters for preceeding stages
% OUTUT:
%    y - output signal
% See dualtree
%
% WAVELET SOFTWARE AT POLYTECHNIC UNIVERSITY, BROOKLYN, NY
% http://taco.poly.edu/WaveletSoftware/

% Tree 1
y1 = w{J+1}{1};
for j = J:-1:2
   y1 = sfb(y1, w{j}{1}, sf{1});
end
y1 = sfb(y1, w{1}{1}, Fsf{1});

% Tree 2
y2 = w{J+1}{2};
for j = J:-1:2
   y2 = sfb(y2, w{j}{2}, sf{2});
end
y2 = sfb(y2, w{1}{2}, Fsf{2});

% normalization
y = (y1 + y2)/sqrt(2);