Method and apparatus for reducing the number of rejected documents when reading bar codes
US4239151A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1979 |
| Grant date | Dec 16, 1980 |
| Priority date | — |
| Expiry date | Apr 19, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/98
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
This specification describes apparatus for reading and decoding data encoded in terms of the spacing between adjacent code bars on a document. The apparatus contains reading means for producing an electrical pulse for each bar recorded on the document as the bar passes the reading element. A counter is used to measure the time between each two pulses and the resultant counts are stored in a memory in the order in which the pulses were produced by the reading means. A microprocessor then compares this stored data with microcoded data representative of properly coded digits. If there is a compare the stored data is shifted out of the memory and into a computer for use. However if there is a no-compare the microprocessor alters the data on the assumption that a particular type of error has occurred and again compares the modified data with the microcoded data. If this results in a compare the modified data is again read out and into the using computer. However if it again results in a no-compare, the processor modifies the stored data a second time on the basis of another assumption and this newly modified data is compared with microcoded data. These successive data modifications and …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.