Microform reading apparatus

Abstract

Abstract @ A microform reader for reading microfilm filmed at a reduction of about 200 times forms an image of a selected page on the microform on a linear solid state sensor which scans down the image of the page to produce a line-by-line or video-type representation of the page for transmission to a remote location. Selected lines of the sensor output are analysed to provide a determination of image parameters and enable the image-forming system to be adjusted to improve the transmitted image quality. Thus each filmed page carries at its head a registration target of well defined shape such that a selected scanned line yields precise information as to the X-Y location of the page. Also selected pages include a focussing target including a pattern carrying a black/white discontinuities. Analysis of the scanned line representing the discontinuities gives a measure of the accuracy of focus enabling appropriate adjustment to be made automatically.

Inventors

• 👤 Melvyn James Lampard

Bibliographic Details