Illumination system with incident beams from near and far dark field for high speed surface inspection of rolled aluminum sheet
US5087822A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 13, 1991 |
| Grant date | Feb 11, 1992 |
| Priority date | — |
| Expiry date | May 13, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8918
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Apparatus and method for inspecting surface quality of a moving sheet of metal illuminates a surface of the moving sheet by the use of at least two lamps. The region which is illuminated by the lamps is inspected by a sensing device. The angle of incidence for the light beams from the lamps are from the near and dark fields. The sensing device picks up highlighted or brightened portions of the sheet due to surface irregularities. By use of a multiplicity of lamps and a single sensing device, such as a video recorder, an inexpensive yet very sensitive system is provided for detecting irregularities in the surface of the moving sheet. The system may be observed by an operator to determine locations of irregularities and as well the system may be adapted to document locations on the moving sheet where the irregularities occur.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.