Currency paper verification and denomination device having a clear image and a blurred image
US5399874A · kind A · utility
Inventors
Key dates
| Filing date | Jan 18, 1994 |
| Grant date | Mar 21, 1995 |
| Priority date | — |
| Expiry date | Jan 18, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K2007/10485
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A linear array of photodiode and phototransistor pairs are positioned on opposite sides of currency paper for denomination determination under reflected light and for verification determination under transmitted light. The focus of one of the photodiodes in each pair is precisely adjusted for the top surface of the currency paper. The focus of the other photodiode in each pair is slightly out of focus at the top surface. A phase diversity algorithm integrates the successive images from both photodiodes to form a clear image. A processor determines the presence or absence of the security feature and correspondingly provides visual or audible indication thereof. The processor contains stored information identifying currency denomination and a comparison is made at the time of verification to also determine the denomination of the proffered currency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.