Golden template comparison for rotated and/or scaled images
US5850466A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 22, 1995 |
| Grant date | Dec 15, 1998 |
| Priority date | — |
| Expiry date | Feb 22, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/7515
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method for Golden Template Comparison (GTC) is provided that can be used to efficiently perform flaw and defect detection on a two-dimensional test image that is at least rotated and/or scaled and/or sub-pixel translated. Run-time inspection speed and accuracy is substantially improved by retreiving a golden template image that is rotated and/or scaled and/or translated in a manner substantially similar to the test image. This is accomplished by storing, in an array, a varied plurality of golden template images, each golden template image being characterized by a different combination of at least rotation and/or scale and/or sub-pixel translation. The array is indexed by the respective quantized rotation and/or quantized scale and/or sub-pixel translation of each version of the golden template image. The array can be either one-dimensional or multi-dimensional. At run-time, the values of the rotation and/or scale and/or sub-pixel translation of each test image are measured, and then quantized, thereby providing a unique index into the multi-dimensional array of reference and threshold images. The reference and threshold images stored at the memory location corresponding to the in…
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