US 4,907,086 A · Method and apparatus for overlaying a displayable image with a second image

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.

Claims15

Dependent claims

A display system, comprising:

a video display providing a visual display from timed video data;
a first frame buffer, connected to said display, for storing data representative of a primary image to be displayed by said display and supplying said timed video data to said display;
a data source providing timed source data corresponding to an overlay image;
a second frame buffer, connected to said data source, for receiving and storing said source data presented by said data source;
a first addressing circuit, connected to said first frame buffer, for presenting address and control signals thereto;
a second addressing circuit, connected to said second frame buffer, for presenting address and control signals thereto;
and
a data bus, connected between said first and second frame buffers, communicating data therebetween free from synchronization with said timed video data and said timed source data, so that the contents of said second frame buffer containing said overlay image is communicated to said first frame buffer for writing thereinto.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus for overlaying a displayable image with a second image

Life of this patent

Method and apparatus for overlaying a displayable image with a second image

Life of this patent

Abstract

Claims15