I mangled up two ideas in my posts before: One thing was taking snaps with a USB connected webcam instead of supplying PNG graphics to the emulated scanner. The other thing was emulating a hand scanner within MAME. Pernod and RB got it right.

NCR DMV- DEC Rainbow- Siemens PCD- ITT 3030-Oly People- Acorn A5000- Olivetti M20