Insert Generator from Photos

Dear 3d scanning community,

I got a little bit of a different question because I search for a software which can generate correctly sized outlines from photos to create 3d printable inserts. While this is not a real 3d scan, it is not a real 2d scan either, as it is based on fully 3d geometry. It should be possible using either spaced QR codes to get the dimensions of an underlying paper, but before I make something myself with python, I wanted to ask if there is anything I didn’t see.
I am sorry that this does not fully fit the topic of 3d scanning, but I do not know where else would be better suited.

Best regards.