%   Made by Gábor Vecsei
%   https://gaborvecsei.wordpress.com/
%   https://twitter.com/GAwesomeBE

clc;
close all;
clear;
workspace;
[filename, pathname] = ...
     uigetfile({'*.jpg';'*.png';'*.tif';'*.*'},'Select an Image file');
fullFileName = fullfile(pathname, filename);
I = imread(fullFileName);
BW = im2bw(I);
BW = ~BW;
st = regionprops(BW, 'BoundingBox', 'Area', 'Centroid',...
    'MajorAxisLength','MinorAxisLength');




[labeledImage, numberOfCircles] = bwlabel(BW);

subplot(1,2,1);
imshow(BW);
title('Original Picture', 'Color', 'black', 'FontSize', 14);

for k = 1 : length(st)
  thisBB = st(k).BoundingBox;
  rectangle('Position', [thisBB(1),thisBB(2),thisBB(3),thisBB(4)],...
      'EdgeColor','r','LineWidth',1 );
end

for k = 1 : length(st)
    center = st(k).Centroid;
    diameter = mean([st(k).MajorAxisLength st(k).MinorAxisLength],2);
    radii = diameter/2;
    hold on
    plot(center(1),center(2),'r*','MarkerSize',5)
    hold off
    text(center(1),center(2),strcat('radian:',num2str(radii)),'Color','green','FontSize', 8);
end

allAreas = [st.Area];
[sortedAreas, sortingIndexes] = sort(allAreas, 'ascend');
smallIndex = sortingIndexes(1);
smallImage = ismember(labeledImage, smallIndex);
st_small = regionprops(smallImage, 'BoundingBox', 'Area');

subplot(1,2,2);
imshow(smallImage);
title('The Smallest Object', 'Color', 'black', 'FontSize', 14);

for k = 1 : length(st_small)
  thisBB = st_small(k).BoundingBox;
  rectangle('Position', [thisBB(1),thisBB(2),thisBB(3),thisBB(4)],...
  'EdgeColor','r','LineWidth',1 );
end