Process for detecting and mapping dirt on the surface of a photographic element
US5436979A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 21, 1992 |
| Grant date | Jul 25, 1995 |
| Priority date | — |
| Expiry date | Aug 21, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/8916
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and associated apparatus for detecting the amount, size, shape, and location of anomalies, such as dirt and scratches, on the surface of a test photographic element after the application of a cleaning procedure and for objectively determining the effectiveness of the film cleaning devices and procedures at removing dirt from photographic negatives and slides and the scanner's sensitivity to the artifacts on the test photographic element's surface. The test photographic element is scanned and the scanned image is digitized and converted to color digital count values. The count values are corrected for systematic errors and a set of context dependent threshold values on the corrected data is computed. If the corrected data passes any of the series of threshold tests it classified as anomalous otherwise it is considered to be background or clean. A series of statistics are calculated for the detected anomalies and are reported to the operator. This report enables the operator to monitor and maintain the quality of the cleaning process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.