Counting

>> clear
>> close all
>> clc

>> I = imread('C:\Temp\Universe.bmp');
>> g = rgb2gray(I);
>> bw = im2bw(g);
>> figure, imshow(bw);
>> bw2 = im2bw(g, 0.3);
>> bw1 = im2bw(g);
>> bw1 = ~bw1;
>> bw2 = ~bw2;
>> b1 = bwboundaries(bw1);
>> figure, imshow(bw1);
>> text(10,10,strcat('\color{green}Objects Found : ',num2str(length(b1))));
>> hold on
>> for k = 1:length(b1) ...
          boundary1 = b1{k}; ...
          plot(boundary1(:,2), boundary1(:,1), 'g', 'LineWidth', 0.2); ...
     end

Universe

Binary (bw1)

Binary Boundary (bw1) found 808 objects

>> b2 = bwboundaries(bw2);
>> figure, imshow(bw2);
>> text(10,10,strcat('\color{red}Objects Found : ',num2str(length(b2))));
>> hold on
>> for k = 1:length(b2) ...
          boundary2 = b2{k}; ...
          plot(boundary2(:,2), boundary2(:,1), 'r', 'LineWidth', 0.2); ...
     end

Binary (bw2)

Binary Boundary (bw2) found 1691 objects

Corner Detection

>> % Create a checkerboard image.
>> I = checkerboard(40,2,2);

>> % Find the corners in the image.
>> C = corner(I);

>> % Display the corners when the maximum number of desired corners is the default setting of 200.
>> subplot(1,2,1);
>> imshow(I);
>> hold on
>> plot(C(:,1), C(:,2), '*', 'Color', 'c')
>> title('Maximum Corners = 200')
>> hold off

Maximum Corners = 200

>> % Display the corners when the maximum number of desired corners is 3.
>> corners_max_specified = corner(I,3);
>> subplot(1,2,2);
>> imshow(I);
>> hold on
>> plot(corners_max_specified(:,1), corners_max_specified(:,2), ...
     '*','Color','m')
>> title('Maximum Corner = 3')
>> hold off

Maximum Corners = 3

>> clear
>> close all
>> clc

>> % Second Example
>> I = imread('Heart.bmp');
>> figure, imshow(I);
>> I = imdilate(I,strel('disk',2));
>> g = rgb2gray(I);
>> bw = im2bw(g);
>> bw = ~bw;
>> figure, imshow(bw);
>> C = corner(bw);
>> hold on
>> plot(C(:,1), C(:,2), 'r*');

Original 

Binary

Corners found

>> clear
>> close all
>> clc

>> % Third Example 
>>I = imread('Football.bmp');
>> figure, imshow(I);
>> g = rgb2gray(I);
>> figure, imshow(g);
>> C = corner(g);
>> hold on
>> plot(C(:,1), C(:,2), 'go');

>> bw = im2bw(g);
>> figure, imshow(bw);
>> D = corner(bw);
>> hold on
>> plot(D(:,1), D(:,2), 'yo');

Original

Points of  Corner in Grayscale

Points of Corner in Binary

--------------------------------------------------------------------- ที่มา : Math Work's document