Method and apparatus for improving video conferencing video capture by distance adaptive filtering
US6275252A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Mar 25, 1997 |
| Grant date | Aug 14, 2001 |
| Priority date | — |
| Expiry date | Mar 25, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/142
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A zoom distance of a camera is determined at a time when a video image is captured. Next, a filtering process is applied to the image based upon the zoom distance. For one embodiment, the process of determining the zoom distance includes establishing a reference focal length of a lens system of the camera and comparing that reference focal length to a measured focal length of the lens system at a time when the video image is captured. Based upon whether the reference focal length is greater than or less than the measured focal length, a filtering process is applied to the image. The filtering process to be applied is such that when the reference focal length is greater than the measured focal length, the filtering process removes more high frequency components from the image than are removed when the measured focal length is greater than the referenced focal length. That is, when the image is recognized as being that corresponding to a wide angle shot, and hence a lower focal length for the lens system, fewer high frequency components are removed from the image during filtering.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.