How to find the margin in an image of the text document?

I have a sample of handwriting. And I want to find the left, right and top margin[i.e., the space between the starting of the writing and the edge of the paper to the left is the left margin]. Please help me with the code.

Answer 1

[Image Analyst]

Did you try to threshold and then use regionprops(L, 'BoundingBox')?

If the shadows on the paper are a problem then call edge() first and then get the bounding box from the edge image.

[Poornima Gokhale]

Sorry sir,I didnt get what you said.

[Image Analyst]

Something like

grayImage = imread(filename);
binaryImage = grayImage < 128; % or whatever value works
% Join into one gigantic blob
binaryImage = bwconvhull(binaryImage);
labeledImage = bwlabel(binaryImage);
% Find the bounding box of all the text together.
measurements = regionprops(labeledImage, 'BoundingBox');
boundingBox = measurements.BoundingBox;
croppedImage = imcrop(grayImage, boundingBox);
imshow(croppedImage);

[Poornima Gokhale]

Thank you. But when i run this code i will get the image with margin cropped. But i want the number of pixels of margin[i.e., length or how much millimeter the margin is on all the sides]. How to modify the above code to get that value . Please suggest me with the code.

[Image Analyst]

If you don't want to crop it, don't call imcrop(). The bounding box gives the [left, top, width, and height] so you can get the margin distances from that. For example the left margin is boundingBox(1), and so on.

[Poornima Gokhale]

Thanks a lot. I got the left and top margin. But is there any way that i can also get the right margin?

[Poornima Gokhale]

What is the unit of the value got from boundingBox(1),boundingBox(2) Is it the number of pixels or is it any other measurement unit?

[Walter Roberson]

Pixels.

[Poornima Gokhale]

thank you. Sir can I get the right margin?

[Image Analyst]

Poornima if you add the width to the left coordinate, what do you get? The right coordinate. Now if you subtract that from the number of columns in the image, what do you get? The right margin. So it would be this:

rightMargin = size(grayImage, 2) - (boundingBox(1) + boundingBox(3));

[Poornima Gokhale]

Thanks a lot sir.

[Image Analyst]

@Prashant Kumar I don't understand. Exactly what kind of color image do you have if it's not RGB? Do you have a multispectral image?

Regardless, somehow you need to process it to arrive at a gray scale image and then you threshold it to get a binary (logical) image. Then you can find the bounding box and all kinds of other information with regionprops().

For example in the multispectral example you don't need to convert it to RGB. You can simply examine the band images and take the band where the ink/handwriting shows the greatest contrast with the paper.

[Image Analyst]

Then I still don't know what you mean by "without converting it into rgb." when it's already RGB. What does "margin" mean? You forgot to post an image where you show the wounds and the margin. Please do so in a new thread and outline them in red or something.

I suggest you post your two images in a new thread, your own, rather than here in @Poornima Gokhale's discussion.

[Image Analyst]

I don't want to answer your question in @Poornima Gokhale's discussion. So like I said, start your own question somewhere else (NOT here) and I'll answer there. @Poornima Gokhale probably doesn't care about your problem.