[Cerium]

Sorting by optical recognition and air guns to separate a falling curtain of product into two output streams is already a product. The development of these machines are the reason that 10 or 15 years ago you stopped seeing bad beans in bulk bean bags. I am involved in the tea industry where they are used to sort tea by grade - stems, bad leaves, broken leaves, full leaves.

Here is a diagram: https://www.satake-usa.com/what-is-optical-sorting.html

[SequoiaHope]

Yes but when I went to the recycling (sorting) facility in San Mateo they remarked that their plastic sorting systems work by infrared reflection and so cannot see black plastic. They said that because of this they are unable to process black plastic entirely. I got the sense that there’s room for improvement.

Bonus slow motion footage of their processing machines: https://imgur.com/gallery/IK5zKkO

[handol]

Reminds me of the library modernization drive in 'Rainbows End'. The book digitizer is basically a wood chipper with lights and high speed cameras in the debris chute.

[analognoise]

There was a company in Japan that would digitize your books and destroy the original (to prevent infringement claims), iirc.