Apparatus for reading a license plate
US4817166A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1986 |
| Grant date | Mar 28, 1989 |
| Priority date | — |
| Expiry date | May 5, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V2201/10
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A video camera produces an image of a license plate on a vehicle, and a scanning apparatus finds a license plate number in the image. The identification of the license plate number is verified in a confidence check section by checking for the presence of a state logo. Next, a character extractor identifies individual characters of the number by finding and tracing a contour along interior portions of the character edges, and the contour length, character height, and character width are then checked in a validity checking section to determine whether they are within predetermined acceptable ranges. To correct for obscuring objects on the license plate, a character alignment section determines the top line and baseline of the license plate number and disregards portions of the characters that appear to be outside of these limits, and a license plate frame correction section is utilized to extract the characters when a portion thereof is obscured by a license plate frame. Once extracted, the characters are recognized by a structural analysis section and a state recognition section recognizes the state logo. Once the state is identified, a verification section rereads the license plate…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.