Compensation for scan line variations in a bar code scanner system
US6494376B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 13, 1999 |
| Grant date | Dec 17, 2002 |
| Priority date | — |
| Expiry date | Sep 13, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In a bar code scanning system, information at the leading and trailing ends of a label is corrected to adjust for distortion due to mechanical aspects of the scan line mechanism that might otherwise render information unreadable. The speed of the scanning spot can be characterized over the course of the scan line. With knowledge of the rate of change of the scan mechanism speed at the ends of the scan line, as well as position information in relation to change in speed over the scan line, a measure of the associated time distortion with respect to elements encoded in the scan line information may be established. In turn, a compensation curve may be determined to identify the offset that may be applied to the collected data to compensate for the variation in speed. In a further aspect, interpolation techniques may similarly be implemented to compensate for the distortion of elements on rounded surfaces; potential offset amounts could be determined and implemented to adjust for character/element width distortion. Such offsets could be used either directly on identified character/element widths, or they may be implemented as part of a secondary, more aggressive technique to fit elemen…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.