iwt2_po.sci

小波分解源代码

function x = IWT2_PO(wc,L,qmf)
// IWT2_PO -- Inverse 2-d MRA wavelet transform (periodized, orthogonal)
//  Usage
//    x = IWT2_PO(wc,L,qmf)
//  Inputs
//    wc    2-d wavelet transform [n by n array, n dyadic]
//    L     coarse level
//    qmf   quadrature mirror filter
//  Outputs
//    x     2-d signal reconstructed from wc
//
//  Description
//    If wc is the result of a forward 2d wavelet transform, with
//    wc = FWT2_PO(x,L,qmf), then x = IWT2_PO(wc,L,qmf) reconstructs x
//    exactly if qmf is a nice qmf, e.g. one made by MakeONFilter.
//
//  See Also
//    FWT2_PO, MakeONFilter
//
//  Copyright Aldo I Maalouf

	[n,J] = quadlength(wc);
	x = wc; 
	nc = 2^(L+1);
	for jscal=L:J-1,
		top = (nc/2+1):nc; bot = 1:(nc/2); all = 1:nc;
		for iy=1:nc,
			x(all,iy) =  UpDyadLo(x(bot,iy)',qmf)'+ UpDyadHi(x(top,iy)',qmf)'; 
		end
		for ix=1:nc,
			x(ix,all) = UpDyadLo(x(ix,bot),qmf) + UpDyadHi(x(ix,top),qmf);
		end
		nc = 2*nc;
	end
	endfunction