CONVERTING CINEMATOGRAPHIC PICTURES INTO VIDEO SIGNALS

摘要

An apparatus is described for converting cinematographic images into video signals. The film gate in which a frame to be scanned is located is illuminated uniformly. The film is scanned by means of a rotatable scanning mirror, which with the aid of an imaging system images one line of the film frame onto one row (three rows for color film) of radiation sensitive detectors. The detectors of a row are read sequentially. The illumination beam has a large aperture angle in a first plane transverse to the direction of film transport and a small aperture angle in a plane transverse to the first plane. The film movement is detected with the aid of a sprocket hole detection system, in which an elongate narrow light spot, whose longitudinal direction is transverse to the direction of film transport, is projected onto the strip of film with the sprocket holes. The position of the scanning mirror is detected with the aid of two gratings of special shape.