Target workpiece inspection apparatus, image alignment method, and computer-readable recording medium with program recorded thereon
US7655904B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 26, 2007 |
| Grant date | Feb 2, 2010 |
| Priority date | — |
| Expiry date | Mar 28, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/95615
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A target workpiece inspection apparatus comprises an optical image acquiring unit to acquire an optical image of a target workpiece, a reference image generating unit to generate a reference image to be compared, a difference judging unit to judge whether an absolute value of difference between pixel values of the images in each pixel at a preliminary alignment position between the images is smaller than a threshold value, a least-squares method displacement calculating unit to calculate a displacement amount displaced from the preliminary alignment position, by using a regular matrix for a least-squares method obtained from a result judged, a position correcting unit to correct an alignment position between the optical image and the reference image to a position displaced from the preliminary alignment position by the displacement amount, and a comparing unit to compare the optical image and the reference image whose alignment position has been corrected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.