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

function [MB,r_geom] = perform_bandelet_transform(M,QT,Theta,dir) 
 
% perform_bandelet_transform - perform the bandelet transform 
% 
%   [MB,r_geom] = perform_bandelet_transform(M,QT,Theta,dir); 
% 
%   M is the data (either an image or a bandelet transform) 
%   QT and Theta represent the quadtree, and should be computed using 
%       [QT,Theta] = compute_quadtree(M,T,j_min,j_max,s); 
% 
%   MB is the bandelet transform. 
%   r_geom is the number bit needed to specity the geometry.    
% 
%   Copyright (c) 2005 Gabriel Peyré 
 
if nargin<4 
    dir = 1; 
end 
 
if size(QT,3)>1 || size(Theta,3)>1 
    warning('Quadtree seems to have been computed using multiple thresholds.'); 
    QT = QT(:,:,1); 
end 
 
n = size(M,1); 
 
MB = zeros(n); r_geom = 0; 
j_min = min(QT(:)); j_max = max(QT(:)); 
 
% display subdivision 
for j=j_max:-1:j_min 
    w = 2^j/n; 
    for kx=0:n/2^j-1 
        for ky=0:n/2^j-1 
            selx = kx*2^j+1:(kx+1)*2^j; 
            sely = ky*2^j+1:(ky+1)*2^j; 
            if QT(kx*2^j+1, ky*2^j+1)==j 
                % this is a leaf, transform it 
                theta = Theta(kx*2^j+1, ky*2^j+1); 
                MB(selx,sely) = perform_warped_wavelet(M(selx,sely),theta,dir);  
                if( theta~=Inf ) 
                    Rg = 2*j-1; 
                else 
                    Rg = 1; % ~3 bits to code no geometry 
                end 
                r_geom = r_geom + Rg; 
            else % add split cost: 1 bit 
                r_geom = r_geom + 1; 
            end 
        end 
    end 
end