Video compositor (Patent)
A system is disclosed for blending two image that makes use of a color map which indicates colors in a foreground can be mixed with the background and how much of each source to mix. One embodiment of the invention restricts the use of the color map to only pixels in the foreground that correspond to a graphic (or effect) in the background. Another embodiment makes use of a gray scale matte which stores blending values for each pixel in the foreground.
Video compositor (pdf)