Aspherical blur filter for reducing artifacts in imaging apparatus
US5438366A · kind A · utility
48Cited by
12References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1994 |
| Grant date | Aug 1, 1995 |
| Priority date | — |
| Expiry date | Nov 21, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/46
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical blur filter having a substantially aspherical shape is used in imaging apparatus to limit high spatial frequencies incident upon an image sensor, and thereby to reduce undersampling artifacts. The filter images a circular blur pattern upon an array of nearby photosites. Due to its aspherical shape, the surface of the filter smoothly varies in relation to the field of view of a zoom lens in the apparatus so that the blur pattern maintains a substantially constant radius despite changes in the focal length of the zoom lens.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.