Color Discriminability for Symbols on CRT Displays

Electronic displays typically are required to display information that must be distinguished by shape and color in various ambient and surround illumination conditions. Color coding of symbols on electronic displays improves human performance at tasks requiring the identification and location of specific information. Effective implementation of color coding on CRT displays is presently limited by the inability of the current theories of color difference formulae in predicting distinguishable colors for small symbols. The formulation of a field size dependent color difference metric will enable symbol and display designers to optimize the use of color on self luminous displays. During the Phase I effort we will develop a theoretical model that aids in the design of symbology for color CRT displays. The effects of ambient illumination and surround color as factors in producing a reliable model for color discriminability also will be addressed in the study. The proposed program will utilize experiments with observers to determine the proper weighting vectors to modify the color difference metric. The effectiveness of a particular set of weighting vectors will be based upon how well the modified color difference metric yields discriminable colors as the field size is decreased under various illumination and surround conditions.