Document scanning system.

摘要

A document scanning system comprises means for directing a light beam on to a document positioned at a scanning station. A lens 26 and mirror 20 are employed to direct light reflected from the document on to a detector 34. To compensate for intensity variations which occur when the document position varies from a nominal position A to positions B or C, a stop 40 is employed to limit the solid angle of collection to retro-scattered light from the document.