Golden template comparison using efficient image registration
US5640200A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 28, 1994 |
| Grant date | Jun 17, 1997 |
| Priority date | — |
| Expiry date | Dec 28, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30148
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Golden Template Comparison (GTC) is a method that can be applied to flaw and defect detection in images of 2-dimensional scenes. When a test image is compared to a golden template image, the images must be registered, and then subtracted. The resulting difference image is then analyzed for features that indicate flaws or defects. The registration step is a major determinant of the performance of GTC, and the invention performs the registration step of GTC using a highly efficient and accurate registration method. The registration method of the invention provides substantial registration of all of the features common to the test image and the golden template image, even when one of the images to be registered is flawed, using a registration metric based on minimization of the sum of the absolute value of the differences between the images to be registered, and an efficient optimization technique, such as a version of gradient descent, wherein a local minimum in a registration metric space is found to the nearest pixel using less computational resources than needed to compute the entire registration metric space.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.