Symbology scanning system for efficiently locating coded symbologies
US6508404B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 18, 2001 |
| Grant date | Jan 21, 2003 |
| Priority date | — |
| Expiry date | Dec 18, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/1443
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A scanner for optically scanning coded symbologies including a signal processing unit for pre-processing the scanned symbology information and a hardware symbology locating unit. An analog signal related to the reflectivity of the different portions of the coded symbology is obtained and is converted to digital gray-scale. The portion of the analog signal which corresponds to the substrate reflectance (absolute contrast) is removed, and the available dynamic range of the analog to digital converter is used only for the information-bearing portion of the signal (relative contrast). Since all of the decodable information is ultimately encoded in binary form, the information-bearing portion of the signal is retained. The hardware symbology locating unit includes a plurality of shift registers, each of which derives a value from an input seed which is based upon the width of a detected coded symbology element. The value of a subsequent input seed is compared to the values generated from a prior input seed. Based upon this comparison, the unit determines whether the size of a subsequent symbology element is a ratio match of a prior symbology element. The presence of a potential coded sy…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.