www.pudn.com > SPIHT_bandelet.rar > test_compression.asv

% test the quadtree construction in wavelet domain 
% 
%   Copyright (c) 2005 Gabriel Peyr? 
 
% set to 0 if you don't want to save the images 
save_images = 0; 
 
name = 'polygons_blurred'; 
name = 'barb'; 
rep = 'images/'; 
 
if save_images 
    warning off; 
    mkdir(rep); 
    warning on; 
end 
 
global wavelet_vm; 
wavelet_vm = 0; 
 
n = 512; 
s = Inf;    % super-resolution on the geometry 
 
% set to: 
%   1 if you want the 3 wavelets bands H/V/D to share the same quadtree 
%   0 for 3 different quadtree (more adaptivity but more bits for geometry). 
options.use_single_qt = 0; 
 
M = load_image(name, n); 
 
% reduce size for speed up 
n = 128; 
M = M(end/2-n/2+1:end/2+n/2, end/2-n/2+1:end/2+n/2); 
 
% remove high transition by projecting 
% on coarse scale wavelet domain 
MW = perform_wavelet_transform(M,log2(n),1); 
M = MW(1:n,1:n); 
 
if save_images 
    warning off; 
    imwrite( M/256, [rep 'original.png'], 'png' ) 
    warning on; 
end 
 
Jmin = 4; 
Jmax = log2(n)-1; 
j_min = 2; 
j_max = 4; 
T = [1:0.5:5, 7:2:15, 20]; 
disp('Computing quadtree.'); 
if ~exist('QT') 
    [QT,Theta] = compute_wavelet_quadtree(M,Jmin,T,j_min,j_max,s, options); 
end 
 
MW = perform_wavelet_transform(M,Jmin, 1); 
 
% to reccord the results 
psnr_wav = []; 
bit_wav = []; 
psnr_band = []; 
bit_band = []; 
% test for psnr 
i = 0; 
for t = T 
    i = i+1; 
    QTt = QT(:,:,i); 
    Thetat = Theta(:,:,i); 
    % direct transform 
    disp('Computing forward bandelet transform.'); 
    [MB,Rbandg] = perform_wavelet_bandelet_transform(M,Jmin,QTt,Thetat,1, options); 
    % quantize 
    MBt = perform_quantization(MB,t); 
    MWt = perform_quantization(MW,t); 
     
    % evaluate the nbr of bits via entropy 
   % Rwav  = evaluate_nbr_bits_wavelets(MW, Jmin, t); 
   % Rband = evaluate_nbr_bits_wavelets(MB, Jmin, t); 
 
    disp('Computing inverse bandelet transform.'); 
    [Mb,Rbandg] = perform_wavelet_bandelet_transform(MBt,Jmin,QTt,Thetat,-1, options); 
     
    disp('Computing inverse bandelet transform.'); 
    Mw = perform_wavelet_transform(MWt,Jmin,-1); 
 
    psnr_wav = [psnr_wav, psnr( Mw,M )]; 
    psnr_band = [psnr_band, psnr( Mb,M )]; 
    %bit_wav = [bit_wav, Rwav]; 
    %bit_band = [bit_band, Rband+Rbandg]; 
end 
 
bit_wav = bit_wav/n^2; 
bit_band = bit_band/n^2; 
plot(bit_wav, psnr_wav, bit_band, psnr_band); 
axis tight; 
legend('Wavelets', 'Bandelets'); 
 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
m1 = min( min(bit_wav), min(bit_band) ); 
m2 = max( max(bit_wav), max(bit_band) ); 
bpp = linspace(m1,m2,200); 
 
interp_psnr_wav = interp1(bit_wav, psnr_wav, bpp); 
interp_psnr_band = interp1(bit_band, psnr_band, bpp); 
 
interp_gain = interp_psnr_band - interp_psnr_wav; 
I = find(~isnan(interp_gain)); 
interp_gain = interp_gain(I); 
bpp = bpp(I); 
plot(bpp, interp_gain); 
title('PSNR Gain wav->band'); 
xlabel('bbp'); 
ylabel('+PSNR'); 
axis tight; 
 
if save_images 
    if wavelet_vm==4 
        str_wav = '7-9'; 
    elseif wavelet_vm==0 
        str_wav = 'haar'; 
    end 
    if options.use_single_qt==1 
        str_geom = 'singlegeom'; 
    else 
        str_geom = 'triplegeom'; 
    end 
    str = [name '_psnrgain_' str_wav '_' str_geom]; 
    saveas(gcf, [str '.png'], 'png'); 
end