www.pudn.com > 666bandelets_toolbox.zip > test_quadtree.m

% test the quadtree construction 
% 
%   Copyright (c) 2005 Gabriel Peyré 
 
 
% set to 0 if you don't want to save the images 
save_images = 0; 
 
rep = 'images/'; 
warning off; 
mkdir(rep); 
warning on; 
 
% size of the image 
n = 128; 
% number of VM of the transforms 
global wavelet_vm; 
wavelet_vm = 0; 
 
name = '3contours'; 
M = load_image(name, n); 
 
j_min = 2; 
j_max = 4; 
T = [1,10,100]; 
disp('Computing quadtree.'); 
[QT,Theta] = compute_quadtree(M,T,j_min,j_max); 
 
% save QT and Theta 
if save_images 
    warning off; 
    imwrite( (QT-min(QT(:)))/(max(QT(:))-min(QT(:))), [rep sprintf('qt_bandelet_space_%d_m%d.png', T)], 'png' ); 
    imwrite( Theta/pi, [rep sprintf('theta_bandelet_space_%d%d.png', T)], 'png' ); 
    warning on; 
 
    str = [rep sprintf('quadtree_bandelet_space_%d', T)]; 
    clf; 
    plot_quadtree(QT,Theta, M); 
    saveas(gcf, str, 'png'); 
 
    clf; 
    plot_quadtree(QT,Theta, M, 2); 
    saveas(gcf, [str, '_geom'], 'eps'); 
     
    clf; 
    plot_quadtree(QT,Theta, M, 3); 
    saveas(gcf, [str, '_struct'], 'eps'); 
end 
 
% choose one of the thresholds 
k = 3; T = T(k); 
 
% direct transform 
disp('Computing forward bandelet transform.'); 
[MB,m_geom] = perform_bandelet_transform(M,QT(:,:,k),Theta(:,:,k),1); 
disp( ['|f|^2 - |B(f)|^2 (should be 0 for an orthogonal transform) --> ' sprintf( '%f', sum(M(:).^2 - MB(:).^2) )] ); 
 
disp('Computing inverse bandelet transform.'); 
[M1,m_geom] = perform_bandelet_transform(MB,QT(:,:,k),Theta(:,:,k),-1); 
 
disp( ['|f-B^-1(B(f)|^2 (should be 0 for a correct reconstruction) --> ' sprintf( '%f', sum( (M(:)-M1(:)).^2 ) )] ); 
 
% performing truncated reconstruction 
MBt = MB .* (abs(MB)>T);	% thresholded transform 
[M1,m_geom] = perform_bandelet_transform(MBt,QT(:,:,k),Theta(:,:,k),-1); 
clf; 
imagesc(M1); 
% number of coefficients used 
m = round( sum( abs(MB(:))>T )+m_geom ); 
 
 
% save image 
if save_images 
    warning off; 
    imwrite( M1/256, [rep sprintf('bandelet_space_%d_m%d.png', T,m)], 'png' ); 
    disp( sprintf('T=%d, #coefficients=%d', T, m) ); 
    warning on; 
end