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 . 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 .