Barcode scanner with linear automatic gain control (AGC), modulation transfer function detector, and selectable noise filter
US7216811B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 16, 2004 |
| Grant date | May 15, 2007 |
| Priority date | — |
| Expiry date | Nov 26, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10851
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
According to embodiments of the present invention, a barcode scanner platform is provided in which the gain of an analog signal representative of a barcode is controlled using a control loop. In embodiments, an MTF detector generates a value (e.g., DC) representative of a low frequency portion (wide or out of optical focus elements) of the analog signal and a second value (e.g., DC) representative of a high frequency portion (narrow elements or in optical focus elements) of the analog signal. The processor uses the first and the second values and a reference amplitude to determine a gain signal. The processor provides the gain signal to an AGC circuit that provides a linear response to the gain signal using matched JFETs. A noise filter can be enabled or disabled based on the first value, the second value, and/or the barcode scanner platform read rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.