Importance

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Abstract

A television special effects system is provided wherein digitized picture elements of any one of a plurality of video input signals are assigned addresses corresponding to the desired location of each picture element in a composite output image. The digitized picture elements are then stored in a memory having a capacity equal to one full TV frame in accordance with the addresses assigned thereto. Each video input may be positioned at any location in the composite output image by adding to or subtracting from the write addresses by means of horizontal or vertical positioning numbers. Each video input may also be compressed in either the horizontal or vertical direction, or both, by means of horizontal or vertical compression factors which control the write address generating means so that certain picture elements of the video input are not stored in memory. A process of interpolation is provided for the luminance component of the digitized picture elements so that the data values stored more closely approximate the values which the data would have at the points at which it is written. A system of priorities is provided among the plurality of video input signals so that each desired input may be selected to occupy a portion of the composite output image to the exclusion of the others, even though they overlap. The stored picture elements are read out of memory by means of a read address generator which is non-synchronous with respect to the plurality of video input signals so that the special effects system also acts as a frame store synchronizer for all of the video input signals. The read address generator may also be controlled by horizontal and vertical compression numbers so that a portion of the composite output image may be magnified to occupy the entire output screen.

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First Claim