iwt_sbs.sci

小波分解源代码

function x = IWT_SBS(wc,L,qmf,dqmf)
// iwt_po -- Inverse Wavelet Transform (symmetric extension, biorthogonal, symmetric)
//  Usage
//    x = IWT_SBS(wc,L,qmf,dqmf)
//  Inputs
//    wc     1-d wavelet transform: length(wc)= 2^J.
//    L      Coarsest scale (2^(-L) = scale of V_0); L << J;
//    qmf     quadrature mirror filter
//    dqmf    dual quadrature mirror filter (symmetric, dual of qmf)
//  Outputs
//    x      1-d signal reconstructed from wc
//  Description
//    Suppose wc = FWT_SBS(x,L,qmf,dqmf) where qmf and dqmf are orthonormal
//    quad. mirror filters made by MakeBioFilter.  Then x can be reconstructed
//    by
//      x = IWT_SBS(wc,L,qmf,dqmf)
//  See Also:
//    FWT_SBS, MakeBioFilter
// 
//  Copyright Aldo I Maalouf

   wcoef = ShapeAsRow(wc);
	[n,J] = dyadlength(wcoef);
	
	dp = dyadpartition(n);
	
	x = wcoef(1:dp(L+1));
	
	for j=L:J-1,
	  dyadj = (dp(j+1)+1):dp(j+2);
	  x = UpDyad_SBS(x, wcoef(dyadj), qmf, dqmf);
	end
	x = ShapeLike(x,wc);
	endfunction