The fate of old notes is a critical issue for central banks that oversee their disposal. These notes cannot be thrown away like ordinary rubbish. Instead, central banks have developed standards to ensure the disposal is safe and secure.
This often involves a type of shredding that slices each note into hundreds of tiny pieces, each typically smaller than about thirty square millimeters. The shredded paper, or increasingly plastic, can then be disposed of, or recycled, off site.
Some central banks have even taken to selling shredded banknotes as souvenirs. And this raises the question of whether it is possible to reassemble the notes and reclaim them at face value.
Clearly manual re-assembly is a challenging task. But now Chung Kong, a PhD student at Hong Kong University, has shown that computer vision can help reassemble shredded notes at least partially.
Kong became intrigued after noticing that the Hong Kong ...
