How can I crop a specific area of an image using Python?

Question

This is an image containing some text, then a text box, then a Signature & after that a bottom line ending the picture.

And the 2nd image is what I want as output using python.

I have several pictures like this, I want the same cropped output for all the images.

Here is what I tried: I used pytesseract to OCR the image 1st to locate the text box determining that as starting point & thresholding to determine the endpoint of the signature area....then tried using OpenCV to crop that area & saving it in a local directory but the approach is not much promising.

Can someone help me to solve the problem?

Answer 1

There are several relatively simple approaches you could try.

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You could use cv2.findContours() to locate the two big black titles "Additional Information" and "Signatures and Certifications" and scale off their position to deduce where the signature is. Your intermediate image might be like this:

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You could use "Hit and Miss" matching to locate the 4 corners of the box "The IRS doesn't require your consent...".

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You could do flood-fills in say, red, starting from white pixels near the centre of the image till you get a red box filled around the right size for the box "The IRS doesn't require your consent...". Then scale from that.

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You could do a flood-fill in black, starting 2/3 of the way down the image and half way across, then find the remaining white area which would be the box "The IRS doesn't require...".

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You could look for the large, empty white area below the signature (using summation across the rows) and scale off that. I am showing the summation across the rows to the right of the original image. You could invert first and look for black. Do the summation with:

rowTotals = np.sum(img, axis=1)