I wonder if a technique like this will work for unshredding documents.
That said, reconstruction of shreds is probably possible in most cases, although there is still lots of research to be done in this space. For example the Fraunhofer Society has a project to reconstruct torn documents of the East German StaSi surveillance agency [1]. There seem to be very few detailed publications on their methods, but I did find a high-level overview [2]
[1] http://www.bstu.bund.de/EN/Archives/ReconstructionOfShredded...
[2] https://doi.org/10.1007/978-1-4471-4763-3_8 (The Springer page is paywalled, but the DOI can help you find cheaper sources.)