System for detecting selective refractive defects in transparent articles
US4610542A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 16, 1984 |
| Grant date | Sep 9, 1986 |
| Priority date | — |
| Expiry date | Nov 16, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/90
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A system of back illuminating a glass container with generally horizontal collimated light having a vertical gradient of brightness produced by placing a showcase light behind the upper area of a diffuser plate. The light passing through the bottle is imaged by a lens into the region of the entrance aperture of a camera having a vertical array of pixels. The lens in the camera is focused on the side of the bottle. The output of the camera will be of a general level equal to the level of illumination of the middle of the diffuser. When a refractive defect in the bottle deflects light from the brightest area of the diffuser into the aperture of the camera, the signal output will rise, and if light from the darkest area of the diffuser is deflected by the defect into the aperture of the camera, the output signal will be substantially less. Thus, the output signal provides a way to discriminate between two types of refractive defects, and by filtering the output signal, the background noise can be eliminated, leaving only the characteristic more abrupt signal produced by a defect.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.