G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
G06K21/00—Information retrieval from punched cards designed for manual use or handling by machine; Apparatus for handling such cards, e.g. marking or correcting
G06K21/04—Information retrieval from punched cards designed for manual use or handling by machine; Apparatus for handling such cards, e.g. marking or correcting in which coincidence of markings is sensed optically, e.g. peek-a-boo system