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

% test for pixel re-ordering and test of different 1D-wavelet scheme 
% 
%   Copyright (c) 2005 Gabriel Peyré 
 
name = 'parabola'; 
n = 256; 
 
% you can play on these two parameter to check  
% the consticency of the scheme with respect 
% to curvature and size. 
c = 0.2;    % curvature of the parabola 
P = 16;     % size of the square 
 
save_images = 0; 
 
% repertory to ouput display 
rep = 'images/'; 
if save_images 
    warning off; 
    mkdir(rep); 
    warning on; 
end 
% svg string for image 
base_str = [rep name '_P' num2str(P) '_c' num2str( round(10*c) ) ]; 
 
Jmin = 3; 
Jmax = log2(n)-1; 
 
if 1 || ~exist('MW') 
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
    % image loading 
    if strcmp(name, 'parabola') 
        % skip high details 
        options.c = c;    % curvature of the parabola 
        M_original = load_image( name, 1024, options ); 
        disp('Creating filetered image.'); 
        MW = perform_wavelet_transform(M_original,Jmax+1); 
        M_original = MW(1:n,1:n); 
    else 
        M_original = load_image( name, n ); 
    end 
    M_original = 256 * rescale(M_original); 
    disp('Performing wavelet transform.'); 
    MW = perform_wavelet_transform(M_original,Jmin); 
end 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% region of interest 
switch lower(name) 
    case 'lena' 
        roi_center = [0.8022, 0.6767]; 
        %     roi_center = [0.875,0.665]; 
    case 'peppers' 
        roi_center = [0.821,0.306];     % line 
        %    roi_center = [0.21,0.136];     % curve 
    case 'barb' 
        roi_center = [0.478,0.62]; 
        roi_center = [0.662,0.388];     % left pant 
    otherwise 
        roi_center = [0.5,0.5]; 
end 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% select a sub square 
j = Jmax;   % scale 
q = 1;      % orientation 
[selx,sely] = compute_quadrant_selection(j,q);   
MWj = MW(selx,sely); 
roi_centern = floor(roi_center*(2^j-1))+1; 
M = MWj( roi_centern(1)-P/2+1:roi_centern(1)+P/2, roi_centern(2)-P/2+1:roi_centern(2)+P/2 ); 
 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% find best geometry 
T = 10; 
s = 12; 
disp('Computing geometry.'); 
[MB,theta] = compute_best_direction(M,T,s); 
disp('Performing displays.'); 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% plot the geometry 
x = -1:2/(P-1):1; 
a = cos(theta)*[1,-1]*1.3; 
b = sin(theta)*[1,-1]*1.3; 
clf; 
hold on; 
imagesc(x,x,M); 
line(b,a); 
hold off; 
colormap gray(256); 
axis image; axis off; 
if save_images 
    saveas(gcf, [base_str, '_geometry.png'], 'png'); 
end 
 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% warp points, plot curves 
[t,u,v,ts,us,vs] = perform_warping(M,theta,P); 
 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% plot 1D functions 
clf; 
subplot( 2,1, 1 ); 
plot( ts, vs, '.-' ); 
title('Real positions plot.'); 
axis tight; 
subplot( 2,1, 2 ); 
plot( 1:length(vs), vs, '.-' ); 
title('Integer-rounded positions plot.'); 
axis tight; 
if save_images 
    saveas(gcf, [base_str, '_1D_functions.png'], 'png'); 
end 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% approximation using various schemes 
w = []; 
e = []; 
lgd = {}; 
 
% HAAR 
y = perform_haar_transform(v); 
w = [w, y]; e = [e, l2error(y)]; 
lgd{end+1} = 'Haar'; 
 
% 7-9 
y = perform_wavelet_transform(v); 
w = [w, y]; e = [e, l2error(y)]; 
lgd{end+1} = 'Wavelet 7-9'; 
 
 
% alpert 
alpert_vm = [ [0;0], [1;0], [0;1], [1;1], [2;0], [0;2] ]; 
pos = [t,u]'; 
y = perform_alpert_transform_2d(v,pos,alpert_vm, 1); 
w = [w, y]; e = [e, l2error(y)]; 
lgd{end+1} = 'Alpert 1,X,Y'; 
 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% plot approximation rates 
sel = 1:(P^2)/2; 
clf; 
plot( log2(sel), log2(e(sel,:)) ); 
ylabel('log2(|f-f_M|^2)'); 
xlabel('M'); 
legend(lgd); 
axis([0, log2(max(sel)), -1, log2(max(e(:)))]); 
if save_images 
    saveas(gcf, [base_str, '_approximation.png'], 'png'); 
end 
 
if exist('ARTICLE_save_square_size') 
    ARTICLE_save_square_size; 
end 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% EPS exports for the article 
v1 = vs( max(end/2-64+1,1):min(end/2+64,length(vs)) ); 
clf; 
stem(v1, 'filled' ); 
axis tight; 
axis off; 
if save_images 
    saveas(gcf, [base_str, '_stem1.eps'], 'eps'); 
end 
 
y = perform_wavelet_transform(v1, 0); 
clf; 
stem(abs(y), 'filled'); 
axis tight; 
axis off; 
if save_images 
    saveas(gcf, [base_str,  'stem2.eps'], 'eps'); 
end 
 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% color display of the image (sexy display for cover ;-) 
q = 16; 
M = M(end/2-q/2+1:end/2+q/2, end/2-q/2+1:end/2+q/2); 
eta = 1/5; 
 
Mr = M*0+1; 
Mv = M*0+1; 
Mb = M*0+1; 
 
I = find(M<0); 
a = rescale( -M(I).*(M(I)<0) ); 
a = a.^eta; 
Mv(I) = 1-a; Mb(I) = 1-a; 
 
I = find(M>0); 
a = rescale( M(I).*(M(I)>0) ); 
a = a.^eta; 
Mr(I) = 1-a; Mv(I) = 1-a; 
 
Mi = ones(q,q,3); 
Mi(:,:,1) = Mr;  Mi(:,:,2) = Mv; Mi(:,:,3) = Mb; 
 
% does this image remind you of something ? 
imagesc(Mi); 
if save_images 
    imwrite(Mi, [base_str, '_color.png'], 'png'); 
end