Method and apparatus for decoding bar code symbols
US6152371A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 12, 1998 |
| Grant date | Nov 28, 2000 |
| Priority date | — |
| Expiry date | Aug 12, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/14
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for reading and decoding one-dimensional (1D) bar code symbols. A 1D bar code symbol is imaged by an optical assembly which includes a cubic phase mask that causes the optical transfer function of the optical assembly to remain approximately constant over a range of distances between the apparatus and the symbol to be read. An electrical representation of the resulting image is converted to a smoothly varying analog image signal. A transition identifying circuit processes the analog image signal, without first applying a recovery function that takes into account the effect of the phase mask, and generates a binary signal which is used to decode the symbol.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.