Spatial frequency filter
US4807981A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1985 |
| Grant date | Feb 28, 1989 |
| Priority date | — |
| Expiry date | Apr 26, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0018
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A spatial frequency filter is adapted to an image sensor having a two-dimensional spatial frequency plane whose first quadrant includes a first prescribed point, whose second quadrant includes a second prescribed point, whose third quadrant includes a third prescribed point and whose fourth quadrant includes a fourth prescribed point. The two-dimensional spatial frequency plane has a vertical axis and a horizontal axis. The spatial frequency filter includes the combination of a primary filter part for providing a first trap line passing through the first prescribed point and a second trap line passing through the third prescribed point, a secondary filter part for providing a third trap line passing through the second prescribed point and a fourth trap line passing through the fourth prescribed point, and a tertiary filter part for providing a fifth trap line passing through the first and fourth prescribed points and a sixth trap line passing through the second and third prescribed points. Each of the first to fourth trap lines crosses over the vertical and horizontal axes. The spatial frequency filter of the present invention so arranged suppresses spurious information along the s…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.