Multi-color video display systems using more than one signal source

Abstract

An improved video display system is provided in which two color images are combinable in a dynamic and self-determining fashion to provide improved contrast, comprehension and display versatility. Two separate video signals that are to be used in generating a single display are converted into sequences of digitally encoded picture elements (pixels). Control signals are generated that are dependent upon the data content of the elements in at least one of the sequences, and these signals are used to govern the mode of combination of the two video signals for individual pixel sets. For example a first video signal of digital character and having varying pixel intensity may be transformed into color values for a first pseudocolor display. A second video signal, derived from an analog source, is digitized and is also transformed into pseudocolor, concurrent with the dynamic generation in real time of the data dependent control signals. Such control signals may be incorporated in either or both of the digitized data sequences, and the second video signal may be digitized with or without adjustment of intensity ranges within variable limits. The two transformed digital signal sequences are then arithmetically or logically combined in accordance with the functions defined by the data dependent control signals. For example, the signals may be added, ANDed, ORed, averaged, subtracted, or one or the other can be blocked, and these functions can be varied, dependent upon the data, in incremental fashion within the display. Consequently, the contrast between the two color images can be selectively enhanced, the data contained in the images can be much more clearly depicted in graphical form, and special effects can be obtained in versatile and discretionary fashion.