Object recognition only and using a phone camera limits my ideas,but off the top of my head: Actors in TV and Internet advertisements Animal scat or Animal fo

Object recognition only and using a phone camera limits my ideas,but off the top of my head: Actors in TV and Internet advertisements Animal scat or Animal footprints What the stains on someones clothes were made from (yuck) How many jelly beans or whatever are in a jar The freshness of produce (especially those pre-made salads that can wilt before you get them home) Poisonous plants and mushrooms