Not able to create vertical lines and recognize clusters about pdftabextract HOT 3 CLOSED

You should get acquainted with the parameters of OpenCV's hough transform and probably experiment with the hough_votes_thresh parameter of the detect_lines method (see the example), i.e. probably set it lower in order to detect more lines. The canny_* parameters can also be helpful, but a lower value of hough_votes_thresh should be enough.
Another note: MIN_COL_WIDTH should be the approx. minimum expected column width in pixels, measured in the scanned page image. I guess your left column's width is smaller, isn't it?

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@internaut Thanks for your reply.

MIN_COL_WIDTH is the width of left column measured in pixels using GIMP measurement tool. It gave me that value.

Sure, I will experiment with lowering the value of hough_votes_thresh.

Is it possible to extract tables like this, a table with only horizontal lines and no vertical lines. To a human eye, this looks like a table and can be read. Can the script help to extract such tables?

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When there are no column borders, they can of course not be detected by Computer Vision algorithms like Hough transform.
You'll probably have to use the distribution of x/y coordinates of the text boxes in order to find regularities (i.e. they will cluster together around certain x-positions) and hence detect the columns.

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