How to thin the image so as to make the thickness of the image to one pixel wide?

Hello,i have an image and i want to thin that word image so as to make the thickness of each word to one-pixel wide to make the stroke width uniform.Please help me.

Answer 1

[Image Analyst]

Try this

binaryImage = grayImage < 128;
% Remove small blobs;
binaryImage = bwareaopen(binaryImage, 500);
% Skeletonize
skeletonImage = bwmorph(binaryImage, 'skel', inf);

Make sure your image is actually gray scale, not color.

[Meghashree G]

Sir this is the output image i got when i tried your code!!!Please fix this..

[Image Analyst]

That's the skeleton of a perfect rectangle. You didn't get your binary image correctly. Apparently the image was already binary, not gray scale. I downloaded it and found that out. Here, try this:

fullFileName = fullfile(pwd, 'will.png');
binaryImage = imread(fullFileName);
% Get the dimensions of the image.  
% numberOfColorBands should be = 1.
[rows, columns, numberOfColorChannels] = size(binaryImage);
if numberOfColorChannels > 1
  % It's not really gray scale like we expected - it's color.
  % Convert it to gray scale by taking only the green channel.
  binaryImage = binaryImage(:, :, 2); % Take green channel.
  binaryImage = binaryImage < 128;
end
% Display the image.
subplot(2, 2, 1);
imshow(binaryImage, []);
title('Original Image', 'FontSize', fontSize, 'Interpreter', 'None');

% Invert it.
binaryImage = ~binaryImage;
% Remove small blobs;
binaryImage = bwareaopen(binaryImage, 500);
% Display the image.
subplot(2, 2, 2);
imshow(binaryImage, []);
title('Binary Image', 'FontSize', fontSize, 'Interpreter', 'None');

% Skeletonize
skeletonImage = bwmorph(binaryImage, 'skel', inf);
% Display the image.
subplot(2, 2, 3);
imshow(skeletonImage, []);
title('Skeleton Image', 'FontSize', fontSize, 'Interpreter', 'None');

% Set up figure properties:
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Get rid of tool bar and pulldown menus that are along top of figure.
set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
set(gcf, 'Name', 'Stem Test', 'NumberTitle', 'Off')

[Meghashree G]

Thanks for the reply sir.. But see the output for this image...in this word,the dot of 'i' is eliminated and even 'r'.

Input image..

This is the output.

How to fix?thinning should be done in such a way that no letters should be eliminated and dots of i and j should not be eliminated.

[Walter Roberson]

Decrease the 500 in binaryImage = bwareaopen(binaryImage, 500);

[Meghashree G]

thank u sir..but i dint get which part is making the word thickness to one pixel wide???

[Image Analyst]

It's this line that makes it one pixel wide:

skeletonImage = bwmorph(binaryImage, 'skel', inf);

To not remove small blobs, change the 500 to a smaller number, like 20 or 50 or whatever

binaryImage = bwareaopen(binaryImage, 20);

The number you input is the size of blobs, plus smaller ones, that it will throw away (remove).

[Vijesh Soorya Rao]

Thank you :)

Answer 2

[Walter Roberson]

bwareafilt to remove the speckles. bwmorph() to skeletonize.

[Meghashree G]

Sorry sir..I dint get you..how do i make the image thickness one pixel wide??please help me with the code.Thank you