Dust and scratch detection for an image scanner
US7355193B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 2004 |
| Grant date | Apr 8, 2008 |
| Priority date | — |
| Expiry date | Feb 16, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8841
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Multiple scans of the same object are obtained, where for any given line on the object to be scanned, the angle of the illumination is different for each scan. The different scans are obtained from different rows of photosensors that are separated. Because the angles of illumination are different, the resulting shadows in each scan are different. The multiple scans may be combined into a single composite color image. In a composite image, a dust particle may generate a series of overlapping shadows, where each shadow is a different color. Searching the composite image for the unique pattern of colors may identify artifacts or defects. Alternatively, the data for one scanned image may be compared to the data for another scanned image, and any differences may be due to shadows, which may indicate defects.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.