The research of redundacy in avionics color palette for on-board indication equipment

Design of modern on-board equipment for visualisation of flight-navigation parameters and geoinformation data (digital map), is concerned with some requirements to quality of visualisation of information to be displayed. This kind of quality may be characterized quantatively by image brightness contrast for each colour displayed on the screen. To provide a stable readibility of image for pilots it is necessary to choose chromaticity coordinates of image elements in according with a special procedure. The purpose of the research is to determine the values of awailable chromaticity coordinates for pixels, composing the displayed image. Multi-Functional Display Units (MFDU) based on plane LCD-panels are used for visualisation of flight-navigation metrics and geoinformation data (GID) in on-board aircraft's equipment. Choice of chromaticity coordinates of image elements was performed to obtain maximal value of brightness contrast in every presumed color, that reserved for avionics. The calculation of chromaticity coordinates based on Maxwell's color mixing triangle by mutual transformations between elements of ?Yplane and decimal codes of RGB-palette, used in software of on-board indication equipment. Numerical values of (x,y)- chromaticity coordinates, which are used for indication of flight-navigation data (one set of colors) and geoinformation data (another set of colours) are obtained. The idea of the research is to evaluate brightness contrast for images displayed in various colors in the presence of external illuminance with various levels up to 75 kLx, producing by special lighting hardware. There samples of MFDU with mounted screens with backlight gas discharge tubes, made by various manufacturers (SEXTANT, NEC, SIEMENS, SHARP), were tested. Quantative estimations of brightness contrast, performed in different colors, shown on the set of charts. Decision-making rule approving the use of RGB-codes is the case if brightness contrast of the test image, displayed in any predefined color, exceeds value two. Results of the research were obtained during experimental design works and may be used by software developers for indication equipment to choose chromaticity coordinates, providing stable visual perception in the precence of high external illuminance.