%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Matching an image using multiscale search      %
%                                               %
%Hao Jiang, Oct 2007                            %
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

scale_levels = 3;
im_target = imread('spider1.bmp');
im_target = im2double(im_target);
imt_pyramid = cell(3,1);
% scale the target image into different levels
for n = 1 : scale_levels - 1
    imt_pyramid{n} = im_target;    
    im_target = imresize(im_target, 0.5);
end

im = imread('spider2.bmp');
im = im2double(im);
figure(1);
imshow(im);
[x,y] = ginput(2);
x = floor(x);
y = floor(y);
imb = zeros(max(y)-min(y)+1, max(x)-min(x)+1, 3);
imb(:,:,1) = im(min(y):max(y), min(x):max(x), 1);
imb(:,:,2) = im(min(y):max(y), min(x):max(x), 2);
imb(:,:,3) = im(min(y):max(y), min(x):max(x), 3);
[tph, tpw, tpd] = size(imb);

pp = [x(1), y(1); x(1) + tpw - 1, y(1);...
      x(1) + tpw - 1, y(1) + tph - 1;...
      x(1), y(1) + tph - 1];
hold on;            
plot([pp(:,1); pp(1,1)], [pp(:,2); pp(1,2)], 'LineWidth', 3, 'Color', [1,0,0]);   
hold off;    

im_template = imb;
ims_pyramid = cell(3,1);

% scale the template into several levels
for n = 1 : scale_levels - 1
    ims_pyramid{n} = im_template;
    im_template = imresize(im_template, 0.5);    
end

tic
% multiscale search
bb = locate_imageblock(im_template, im_target);
for n = scale_levels - 1 : -1 : 1
    bb = bb * 2;
    bb = local_search(ims_pyramid{n}, imt_pyramid{n}, bb(1,1), bb(1,2));
end
toc

figure(2);
imshow(imt_pyramid{1});
hold on;
plot([bb(:,1); bb(1,1)], [bb(:,2); bb(1,2)], 'LineWidth', 3);   
hold off;