How to find maximum and minimum coordinates of a binary Image?

I have a color image, I converted it to black and white and removed noises. Now I want to find the Xmax, Ymax, Xmin, Ymin (maximum and minimum coordinates)of the white object in my Image so that I can draw a rectangle border around the Object. How can I achieve this. Please guide me!

Here is my image.

https://plus.google.com/photos/118325781165366298178/albums/5857527741212679793

Answer 1

[Image Analyst]

This will do that for you:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures if you have the Image Processing Toolbox.
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 20;

% Read in demo image.
folder = 'C:\Users\Junaid\Documents';
baseFileName = '1.jpg';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
% Check if file exists.
if ~exist(fullFileName, 'file')
  % File doesn't exist -- didn't find it there.  Check the search path for it.
  fullFileName = baseFileName; % No path this time.
  if ~exist(fullFileName, 'file')
    % Still didn't find it.  Alert user.
    errorMessage = sprintf('Error: %s does not exist in the search path folders.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
rgbImage = imread(fullFileName);
% Get the dimensions of the image.  
% numberOfColorBands should be = 1.
[rows columns numberOfColorBands] = size(rgbImage);
% Display the original gray scale image.
subplot(2, 2, 1);
imshow(rgbImage, []);
title('Original Grayscale Image', 'FontSize', fontSize);
% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);
% Give a name to the title bar.
set(gcf,'name','Demo by ImageAnalyst','numbertitle','off') 

% Binarize the image by thresholding the green channel
binaryImage =rgbImage(:,:,2) > 128;
% Get rid of border.
binaryImage = imclearborder(binaryImage);
subplot(2, 2, 2);
imshow(binaryImage, []);
title('Binary Image', 'FontSize', fontSize);

% Find limits;
vertical = any(binaryImage, 2);
horizontal = any(binaryImage, 1);
row1 = find(vertical, 1, 'first') % Y1
row2 = find(vertical, 1, 'last') % Y2
column1 = find(horizontal, 1, 'first') % X1
column2 = find(horizontal, 1, 'last') % X2

boxY = [row1 row1 row2 row2 row1];
boxX = [column1 column2 column2 column1 column1];
hold on;
plot(boxX, boxY, 'r-');

Answer 2

[Walter Roberson]

bb = regionprops(YourImage, 'BoundingBox');
rectangle( 'Position', bb.Boundingbox );