Systems and methods for compensating for streaks in images
US7347525B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 28, 2006 |
| Grant date | Mar 25, 2008 |
| Priority date | — |
| Expiry date | Jun 28, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/4078
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Defects in an image may give rise to visible streaks, or one-dimensional defects in an image that run parallel to the process direction. One known method for compensating for streaks introduces a separate tone reproduction curve for each pixel column in the process direction. A compensation pattern according to this invention ha alignment marks before and after a halftone compensation region. The alignment marks provide alignment between the printer pixel grid and a scanning pixel grid. The line width of each alignment mark and the gray level in each pixel column of each gray level portion is measured and analyzed to produce a local tone reproduction curve for each pixel column and associated line width. The line widths of the alignment marks can be remeasured to adjust the local tone reproduction curves to compensate for the streak defect when printing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.