Thin-film latent open optical detection with template-based feature extraction
US5448650A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 1994 |
| Grant date | Sep 5, 1995 |
| Priority date | — |
| Expiry date | Feb 18, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30141
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Defects and latent defects are detected in connection patterns on a substrate by automated optical testing using bright field illumination and feature extraction template yielding an improved degree of feature discrimination. The feature extraction templates include angularly disposed vectors requiring detection of a predetermined (e.g. foreground) image value with a predetermined distance and a vector angularly interposed between those vectors which requires no detection of the predetermined image value within a distance which is greater than the predetermined distance. Thus, for successful detection of a defect, a portion of one of a set of templates having such a vector condition configuration must be wedged between areas of an image of a surface having the predetermined image values. This technique is implemented on commercially available automated optical inspection tools and results in avoidance of false detections even in the presence of a high density of image artifacts caused by the topologically sensitive bright field illumination employed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.