www.pudn.com > SPIHT_bandelet.rar > perform_wavelet_transform.m

function MW = perform_wavelet_transform(M,Jmin,dir, options) 
 
% perform_wavelet_transform - a wavelet transform 
% 
%   MW = perform_wavelet_transform(M,Jmin,dir,options); 
% 
%   You can replace this code with your favorite 
%   wavelet transform. 
% 
%   MW must be stored in "Mallat's order",  
%   ie ie has the same size as M, with various 
%   scales and orientation packed from up-left  
%   to bottom right. 
% 
%   Copyright (c) 2005 Gabriel Peyré 
 
options.null = 0; 
if nargin<2 
    Jmin = 1; 
end 
if nargin<3 
    dir=1; 
end 
 
if size(M,3)>1 
    MW = M; 
    for i=1:size(M,3) 
        MW(:,:,i) = perform_wavelet_transform(M(:,:,i),Jmin, dir, options); 
    end 
    return; 
end 
 
 
% number of dimension 
ndim = length(size(M)); 
if ndim==2 && ( size(M,2)==1 || size(M,1)==1 ) 
    ndim=1; 
end 
 
global wavelet_vm; 
if isfield(options, 'wavelet_vm') 
    wavelet_vm = options.wavelet_vm; 
else 
    if isempty(wavelet_vm) || ndim==2 
        wavelet_vm = 4; 
    end 
end 
 
% test if wavelab is available 
if ~exist('MakeBSFilter') 
    wavelet_vm = 0; % use haar transform, sorrrrry 
end 
 
% retrieve the 7-9 CDF biorthogonal filters 
if wavelet_vm>1 
    [qmf,dqmf] = MakeBSFilter( 'CDF', [wavelet_vm,wavelet_vm] ); 
end 
 
% compute biorthogonal wavelet transform 
if ndim==1 
    if wavelet_vm>1 
        if dir==1 
            MW = FWT_SBS(M,Jmin,qmf,dqmf); 
        else 
            MW = IWT_SBS(M,Jmin,qmf,dqmf); 
        end 
    else 
        MW = perform_haar_transform(M,Jmin,dir); 
    end 
else 
    if exist('qmf') && wavelet_vm>0 
        if dir==1 
            MW = FWT2_SBS(M,Jmin,qmf,dqmf); 
        else 
            MW = IWT2_SBS(M,Jmin,qmf,dqmf); 
        end 
    else 
        % no wavelab: use mex haar transform instead (it uses Jmin==1) 
        if dir==-1 
            % makes conversion Mallat's order -> inplace order 
            M = reorder_coefs(M,0,-1); 
        end 
        MW = perform_haar_transform(M,Jmin,dir); 
        if dir==1 
            % makes conversion inplace order -> Mallat's order 
            MW = reorder_coefs(MW,0,1); 
        end 
    end 
end