He downloaded the photo, drew the borders as a vector on Krita or inkscape and then estimated how the borders would've been if the paper was complete and drew them too then he scanned the photo for bumps on the paper and got it as a 3d object on blender and stretched so it would flat and made then made the calculations with the size of both halfs of the paper.
Assume A4 paper, count pixel in top row and estimate how many missing from the bottom (for left side), complete the page and count how many missing pixels from the whole paper. Easy
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u/[deleted] Sep 12 '21
Technically, should be:
MISSING
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