The Register recently learned of a drone designed to photograph supermarket shelves so that image analysis can automatically figure out what stock needs to be re-ordered
!?
Wouldn't it just be easier to output the barcode references from the tills to a database so you know what's been sold, and then just reorder the difference to take you up to the preset stock level? ie, you have 3 boxes of 12 items each of item X, and once 12 items have been used the computer system reorders one box of item X and tasks a meatbag to stick in on a shelf.
Obviously subject to small variances due to theft, but that's what stockchecks and human management are for.