Shadowless spherical illumination system for use in an article inspection system
US5201576A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 30, 1992 |
| Grant date | Apr 13, 1993 |
| Priority date | — |
| Expiry date | Apr 30, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/065
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A shadowless illumination system (10) according to the present invention includes a spherical chamber (14) having a chamber entrance opening (18) and a chamber exit opening (20). The inside surface (32) of the spherical chamber is coated with highly reflective flat white paint. A clear rigid plastic cylindrical tube (22) is positioned in the spherical chamber between the chamber entrance and exit openings. A circular fluorescent ring lamp (36) is positioned inside the spherical chamber to form an annulus around the tube. The lamp and the white inside surface of the spherical chamber provide shadowless illumination for articles (30) that are dropped or otherwise projected through the tube. The articles are inspected as they pass through the tube by at least two video inspection cameras (52 and 62) that view opposite sides of the articles through respective viewing openings (44 and 48). Whenever no articles are present in the image plane of a camera, the lamp provides a saturated background for the camera. A ballast (140) controls the voltage to the lamp to provide constant light intensity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.