Fluorescent reference tracks for an image scanning system

Abstract

Fluorescent reference tracks for use in correcting for geometric and other distortions in an image scanning system comprising a rotatable cylindrical drum assembly and an optical subsystem disposed within a protective housing is disclosed. Fluorescent reference tracks illuminable by light outside the visible spectrum, such as ultraviolet (UV) light, are disposed on inner surfaces of inwardly directed film support shoulders of the drum assembly. Respective edges of film containing an image to be scanned are retained on the outer surfaces of the film support shoulders of the drum assembly. As the film is rotated by the drum assembly past a primary light source disposed adjacent one side of the drum, light from the primary light source is directed through the film and is focused by a lens assembly disposed internal to the drum assembly onto a sensor assembly disposed at an opposite side of the drum assembly, which scans the transilluminated film portion. Simultaneously, UV light from secondary light sources is directed toward the respective inner surfaces of the portion of the support shoulders supporting the transilluminated film portion, such that a fluorescing image of the reference tracks flanking the film portion is reflected back through the lens assembly and scanned by the sensor assembly simultaneously with the film image portion.