Shading correction method and apparatus
US5347370A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 1993 |
| Grant date | Sep 13, 1994 |
| Priority date | — |
| Expiry date | Dec 28, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/401
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Shading correction is effected by partitioning a white standard surface into a plurality of scanning blocks having the same number of scanning lines, scanning the standard surface by block to determine block median values in a first processing stage, determining global median values from the block median values in a second processing stage, and subjecting objective image data read from a given original image to arithmetic such as proportioning calculation. With the two-stage processing, shading distortion caused due to nonuniformity in sensitivity of an image scanning system can be rationally and reliably corrected to a high degree with a simple processing circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.