Method and apparatus for overlaying a displayable image with a second image
US4907086A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 4, 1987 |
| Grant date | Mar 6, 1990 |
| Priority date | — |
| Expiry date | Sep 4, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2360/126
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The overlaying of video image data from an external source, such as a video camera, onto a representation of display data becomes accomplished by using a serial port of an auxiliary frame buffer to receive the serial data from the external source. The source data then becomes transferred from serial registers included within the auxiliary frame buffer into the randomly accessible array of the auxiliary frame buffer. Subsequent execution of a DMA (Direct Memory Access) places the source data overlaid into the image data in the master frame buffer for communication to the video display. Separate designation of the memory address in the auxiliary frame buffer and the main frame buffer allow the overlaying of data from the auxiliary frame buffer into the main frame buffer asynchronously or in a manner not requiring synchronization of the displayed positions relative to one another.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.