Exposure control apparatus for use with optical readers
US5831254A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 18, 1995 |
| Grant date | Nov 3, 1998 |
| Priority date | — |
| Expiry date | Dec 18, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10752
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An exposure control apparatus for use with optical readers, such as bar code readers, which utilize photosensitive image sensors. An illumination signal generating circuit generates an illumination signal having a magnitude that varies in accordance with the time averaged value of the illumination level at the image sensor. A window detecting circuit periodically samples the illumination signal to determine if that signal is or is not within a window of acceptability. Exposure period determining circuitry uses the output of the window detecting circuit to upwardly or downwardly adjust the value of a control variable as necessary to cause the illumination signal to approach, enter and remain within the window of acceptability.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.