Bar code reader
US4044227A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 7, 1975 |
| Grant date | Aug 23, 1977 |
| Priority date | — |
| Expiry date | Aug 7, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10861
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A compact, self-clocking bar code has a multi-width acquisition bar and a plurality of contiguous data spaces. Data bars occupy selected data spaces to define a code. The bar code is emplaceable on an article or label for identification or other purposes. Scanning means redundantly line scan across the bars and produce a video signal having an amplitude pattern corresponding to the scanned bar code. A decoder includes window logic confining video processing to a read window in the video field in which the scanned bar code is to appear. The decoder includes a high frequency clock circuit and means initially processing, or "digitizing", the raw video signal. A strobe circuit incorporates a side loading up-down counter which initially counts and stores clock pulses in proportion to the scanned width of the acquisition bar. The counter repetitively counts from the stored count down to zero to provide a series of strobe pulses which are to coincide with scanning beam movement across the centers of the data spaces in the bar code during a given scan line. Detector circuitry compares the video amplitudes coincident with the series of strobe pulses, with a stored reference code, and when s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.