Automatic background scene defocusing for image compositing
US6646687B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 16, 1999 |
| Grant date | Nov 11, 2003 |
| Priority date | — |
| Expiry date | Apr 16, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/272
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention is a method and apparatus for automatically defocusing a background scene as the background scene is being composited with a foreground subject during the photography of the subject, where the background scene becomes increasingly defocused as the subject appears to approach the camera. A source of background image signals is connected to a background input of a compositing device capable of averaging a selected group of background pixels. A source of foreground image signals is connected to a foreground input of the compositing device. A matte signal generated by the compositing device is accessed and the matte signal is used to determine the ratio of foreground subject area to image frame area. The area ratio is then used to select, for each pixel in said background image, a number of adjacent pixels to be averaged to form an average pixel level. The signal levels at each pixel in the background scene are replaced with the average pixel level. This results in a defocusing of the background scene in proportion to the apparent reduction in camera to subject distance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.