Image defect inspection method, image defect inspection apparatus, and appearance inspection apparatus
US7492942B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 17, 2005 |
| Grant date | Feb 17, 2009 |
| Priority date | — |
| Expiry date | Apr 27, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/95607
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In an image defect inspection method and apparatus, which detects a gray level difference between the corresponding portions of two images, automatically sets a threshold value based on the distribution of the detected gray level difference, compares the detected gray level difference with the threshold value, and judges one or the other of the portions to be defective if the gray level difference is larger than the threshold value, provisions are made to reduce the occurrence of false defects when there is a brightness difference between the two images undergoing the comparison. In the image defect inspection method, the brightness difference between the two images is computed (S106), and the threshold value is determined in such a manner that the threshold value increases with the computed brightness difference (S107).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.