04800432 is referenced by 75 patents and cites 5 patents.

A video difference key generator has a stored reference video image. An input video image is compared with the reference video image by an absolute difference circuit which substracts corresponding pixels of the two video images, the smaller from the larger, to produce a difference video image. The difference video image may be filtered, and then is input to a transfer function circuit to produce an output which may be used as a key signal for compositing video images.

Title
Video Difference key generator
Application Number
6/922976
Publication Number
4800432
Application Date
October 24, 1986
Publication Date
January 24, 1989
Inventor
Steven M Parkes
Davis
CA, US
Ronnie D Barnett
Nevada City
CA, US
Agent
Francis I Gray
Assignee
The Grass Valley Group
CA, US
IPC
H04N 9/75
H04N 5/275
H04N 5/14
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