OPTICAL SCANNER FOR READING BAR CODES DETECTED WITHIN A LARGE DEPTH OF FIELD

Optical Scanner for Reading Bar Codes Detected Within a Large Depth of Field This disclosure describes a technique for reading bar codes scanned by focussed scan lines having different focal lengths where at least one of the scan lines has a beam that is small relative to irregularities of the surfa...

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Bibliographic Details
Main Author DICKSON, LEROY D
Format Patent
LanguageEnglish
French
Published 03.01.1989
Edition4
Subjects
CALCULATING
COMPUTING
COUNTING
HANDLING RECORD CARRIERS
OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
OPTICS
PHYSICS
PRESENTATION OF DATA
RECOGNITION OF DATA
RECORD CARRIERS
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Summary:Optical Scanner for Reading Bar Codes Detected Within a Large Depth of Field This disclosure describes a technique for reading bar codes scanned by focussed scan lines having different focal lengths where at least one of the scan lines has a beam that is small relative to irregularities of the surface on which the label appears. The scan lines are generated using a holographic disk so as to have a predetermined focal length and focal zone. The focal zone of each generated scan line overlaps the focal point of at least one adjacent scan line. Any bar code label which might be scanned by a beam so small that it would be degraded by surface scatter noise is also scanned by a slightly larger beam. The slightly larger beam "averages out" the surface scattering noise to produce a smoother or cleaner return signal.
Bibliography:Application Number: CA19870536699