Method of and apparatus for inspecting surface defects
US5135303A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1991 |
| Grant date | Aug 4, 1992 |
| Priority date | — |
| Expiry date | Feb 20, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B33/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates to a method of inspecting a defect on a surface of a test piece, and to an apparatus using this method. The method comprises the steps of dividing the surface of the test piece into a plurality of inspection regions so as to detect image signals from said plurality of inspection regions thus divided; measuring feature values of background levels from image signals detected at divided inspection regions adjacent to the plurality of inspection regions thus divided; and representing the image signals detected at the adjacent divided inspection regions in binary form on the basis of threshold values set based on the measured feature values, thereby detecting fine defects on the surface of the test piece based on the image signals represented in binary form.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.