ABSTRACT
Photographic film is an imaging detector or area detector, in that a single exposure produces a two-dimensional record of the intensity-modulated image on the film surface. Mechanical scanning systems usually involve optics consisting of rotating or oscillating mirrors or apertures in a rotating disc such as the Nipkov disc. The simplest scanning system uses a rotating plane mirror in conjunction with various photographic lenses to produce a conventional two-dimensional film record. The scanning lens is fixed and is the final imaging element in the system. Unlike a conventional lens, which has an internal entrance pupil, suitable design places its entrance pupil externally in the plane of a scan element such as a polygon facet. Screened images consisting of half-tone dots have been traditionally produced using process cameras and optical screens. The array is produced by a beamsplitter and individually controlled by acousto-optic modulation from image separation information obtained by a laser scanner.
