Optical scanner using tilted film media

Abstract

The method and apparatus for using a light beam to scan media, particularly radiographic film media, for digitization wherein the scanning beam and the media transport path are optimized to minimize interference of the incident directly transmitted scanning beam with light internally reflected back by the light exit surface of the media, which gives rise to significant modulation of the transmitted intensity and forms contour or fringe patterns which follow small variations in the media thickness. An optical light beam shaping system is employed to generate a generally elliptical or elongated cross-section light beam having a major and minor axis. A scanner deflects the light beam through a predetermined, flat scanning angle in a scan direction forming a scanning line on the incident surface of the film media. The film media is transported past the scanning light beam such that successive lines of the media are scanned. Preferably, the transport mechanism orients the film media at a tilted angle to the flat scanning angle of the deflected light beam to minimize the overlap of light reflected back at the light exit surface with incident light at all points of the deflected light beam through the flat scan angle. Preferably, the generally elongated light beam is rotated relative to the cross-scan direction of the film media to allow for the use of a relatively smaller tilt angle than would be necessary with circular or non-rotated generally elongated light beams.