Optical motion picture film inspection system

摘要

A motion picture film flaw detection system wherein a single inspection location is employed at which sound track side edge defects, sprocket hole side edge defects, thickness variations, and defective sprocket holes are analyzed by optical sensors so that no physical contact on the film by feeler arms or the like occurs. Film wear such as by scratching and rubbing is reduced since minimal contact occurs with a surface of the film as it travels through the system. The sprocket holes are analyzed by optics which provide a real image on a projection plane at which location excessive elongation of the sprocket holes is checked. Detection circuits are provided connecting to the optical sensors which derive a reference which automatically tracks averaged or weighted overall signal levels for comparison to signal variations caused by film thickness changes or film flaws. Accordingly, variations in optical system performance are automatically compensated for.