How to complete table border lines with OpenCV?

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Hi here,

I am working on extracting table border from PDF files. As below is the raw table border I extracted. You can tell, because of the missing part in tables, there are some missing parts in the extracted borders.

With OpenCV, is there a way to complete the table border lines with Hough lines transform etc. ? The lines could be infinity long, because I am more interested in the crossing points so I can reconstruct the table later with reference to some template tables.

Thanks in advance!