ifwt2   

 ifwt2.m

 Inverse fast 2D wavelet transform.

 Usage: x = ifwt2(w, g0, g1, J, sym);
 x - mxn output image (min(m,n) must be divisible by 2^J) 
 w - mxn input image of wavelet coeffients
 g0 - lowpass reconstruction filter
 g1 - highpass reconstruction filter
      g0 and g1 should be zero padded appropriately so that they have the
      same length, and this length is even.
 J - number of levels in the filter bank.
     Right now, it must be chose so that n*2^(-J) >= length(g0)
 sym - How the input was extended when the forward transform was taken.
     sym=0: periodization
     sym=1: type-I symmetric extension ( [... x(2) x(1) x(2) x(3) ...])
            The wavelet filters must have type-I even symmetry 
            (e.g. daub79)
     sym=2: type-II symmetric extension ( [... x(2) x(1) x(1) x(2) x(3) ...])
            The lowpass filter must have type-II even symmetry, 
            The highpass filter must have type-II odd symmetry.
            (e.g. daub1018)

 Written by: Justin Romberg
 Created: April 2007

0001 % ifwt2.m
0002 %
0003 % Inverse fast 2D wavelet transform.
0004 %
0005 % Usage: x = ifwt2(w, g0, g1, J, sym);
0006 % x - mxn output image (min(m,n) must be divisible by 2^J)
0007 % w - mxn input image of wavelet coeffients
0008 % g0 - lowpass reconstruction filter
0009 % g1 - highpass reconstruction filter
0010 %      g0 and g1 should be zero padded appropriately so that they have the
0011 %      same length, and this length is even.
0012 % J - number of levels in the filter bank.
0013 %     Right now, it must be chose so that n*2^(-J) >= length(g0)
0014 % sym - How the input was extended when the forward transform was taken.
0015 %     sym=0: periodization
0016 %     sym=1: type-I symmetric extension ( [... x(2) x(1) x(2) x(3) ...])
0017 %            The wavelet filters must have type-I even symmetry
0018 %            (e.g. daub79)
0019 %     sym=2: type-II symmetric extension ( [... x(2) x(1) x(1) x(2) x(3) ...])
0020 %            The lowpass filter must have type-II even symmetry,
0021 %            The highpass filter must have type-II odd symmetry.
0022 %            (e.g. daub1018)
0023 %
0024 % Written by: Justin Romberg
0025 % Created: April 2007