Comprehensive electronic compositing system
US4100569A · kind A · utility
Inventor
Key dates
| Filing date | Sep 30, 1977 |
| Grant date | Jul 11, 1978 |
| Priority date | — |
| Expiry date | Sep 30, 1997 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC10N2040/50
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a system for combining foreground video images with background video images, using the so-called "blue-screen" (or special background color) technique, a comprehensive control system is provided which accommodates a broader range of foreground objects, permits the careful coordination of control of the blue of the foreground with the level of the background signals, and also permits precise shadow control in accordance with the artistic requirements of the scene to be produced. To properly control the level of the blue from the foreground and to properly distinguish between situations where the video signal arises from solid or partially transparent actual foreground objects and where it originates from the blue screen, various electrical adjustments are provided for accommodating different types of foreground objects. One of the adjustments for controlling the blue foreground has three terms, one limiting the level of blue to the amount of green present in the signal, the second permitting an increase in the blue signal in accordance with a function of the positive value of green minus red, and a third term permitting increase of the amount of blue signal in accordance with a f…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.