How to detect hand?

INPUT IMAGE:

MATLAB CODE (also attached):

clear all; close all; clc image=imread('a_ASL3.jpg'); BW=binary_image(image); BW = ~BW; st = regionprops(BW, 'BoundingBox' ); for k = 1 : length(st) thisBB = st(k).BoundingBox; rectangle('Position', [thisBB(1),thisBB(2),thisBB(3),thisBB(4)],... 'EdgeColor','r','LineWidth',2 ) end

OUTPUT IMAGE:

PROBLEM I want bounding box just around hand so that I can crop it and do further operations but I am getting image as output in which there are bounding box around every object.

[Poornima Gokhale]

I tried this code for my image.But its not working properly. How to modify?? And i want an enlarged image of individual letter to save that letter. Please help me

Answer 1

[Image Analyst]

Try this:

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
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 a color demo image.
folder = 'C:\Users\Explorer\Documents';
baseFileName = 'a_ASL3.jpg';
% Get the full filename, with path prepended.
fullFileName = fullfile(folder, baseFileName);
if ~exist(fullFileName, 'file')
  % 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.', fullFileName);
    uiwait(warndlg(errorMessage));
    return;
  end
end
grayImage=imread(fullFileName);
% Get the dimensions of the image.  
% numberOfColorBands should be = 1.
[rows, columns, numberOfColorBands] = size(grayImage);
if numberOfColorBands > 1
  % It's not really gray scale like we expected - it's color.
  % Convert it to gray scale by taking only the green channel.
  grayImage = grayImage(:, :, 2); % Take green channel.
end
% Display the original gray scale image.
subplot(2, 2, 1);
imshow(grayImage, []);
axis on;
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') 

binaryImage = grayImage < 128;
% Display the image.
subplot(2, 2, 2);
imshow(binaryImage, []);
title('Binary Image', 'FontSize', fontSize);

% Label the image
labeledImage = bwlabel(binaryImage);
measurements = regionprops(labeledImage, 'BoundingBox', 'Area');
for k = 1 : length(measurements)
  thisBB = measurements(k).BoundingBox;
  rectangle('Position', [thisBB(1),thisBB(2),thisBB(3),thisBB(4)],...
  'EdgeColor','r','LineWidth',2 )
end

% Let's extract the second biggest blob - that will be the hand.
allAreas = [measurements.Area];
[sortedAreas, sortingIndexes] = sort(allAreas, 'descend');
handIndex = sortingIndexes(2); % The hand is the second biggest, face is biggest.
% Use ismember() to extact the hand from the labeled image.
handImage = ismember(labeledImage, handIndex) 
% Now binarize
handImage = handImage > 0;
% Display the image.
subplot(2, 2, 3);
imshow(handImage, []);
title('Hand Image', 'FontSize', fontSize);

[Explorer]

Thank you. Can you please write few more lines for cropping hand?

[Image Analyst]

You shouldn't need to crop it, but if you want to, say to magnify it, you can simply call imcrop(). Here are the lines you can add:

% Crop out hand
croppedImage = imcrop(handImage, measurements(handIndex).BoundingBox);
% Display the image.
subplot(2, 2, 4);
imshow(croppedImage, []);
title('Cropped Hand Image', 'FontSize', fontSize);

So, if I've answered your original question, don't forget to mark it "Accepted." Thanks, and good luck with your project.

[Explorer]

Thank you very much :)

[Explorer]

rectangle('Position', [thisBB(1),thisBB(2),thisBB(3),thisBB(4)],... 'EdgeColor','r','LineWidth',2 )

How to know positions in numbers above lines?

These lines are from code mentioned above.

[Image Analyst]

You measured the bounding boxes with regionprops. The positions/numbers were measured by regionprops().

thisBB is the bounding box of just one of the boxes. If they are in a matrix (like in between brackets like I did) immediately after the 'Position' keyword, then it will consider those numbers as the position numbers.

[Explorer]

Okay thanks

[Maaz Muslim]

How to save bounding box image?

[Akib Rahman]

@Image Analyst, I tried this code but, it doesn't work for my image! My image is given below

My original image is given below:

But I need a code, which will detect in that way!

Thanks.

[Image Analyst]

Exactly what part doesn't work? I see bounding boxes over the regions, so at least that part works. Does something after that not work, like the sort() function?

[imrankhan ajees]

not working for all inputs it will work for one input only

[Image Analyst]

From my code

width = thisBB(3)
height = thisBB(4)

Answer 2

[Ranjitha]

How to find the length and width for the given code.?? please do help with this.. Can you please let me know what all changes has to be made for the existing code to find length and width of the hand image.