a) A method of combining two video images. The most common example of chroma keying is the news weather person standing in front of a weather map. The details of the process are, a camera is pointed at the weather person who is standing in front of a bright blue or green background. The weather person and bright-blue or green background image is fed into a computing device along with the image of the weather map. Wherever the computing device sees the bright-blue or green background, it displays the weather map. Wherever the computing device does not see bright blue or green, it shows the weather person.

b) A process for controlling the overlay of one video image over another, the areas of overlay being defined by a specific color or chrominance in one of the images. More versatility is available when working in the digital mode than in the analog since the color to define the effective mask can be more precisely specified. Effective use of chroma key frequently required high definition in the color image and, therefore, full bandwidth R, G, B is preferred. Linear key provides an alternate method for control of the overlay.

c) Chroma keying is the process of controlling the overlay of one video image over another. The overlay is defined by a specific color or chrominance in one of the images.