Visual Characteristics of Displaying Air Navigation Parameters and Geoinformation Data in Avionics
Keywords:
Ergonomics, Chromaticity Coordinates, Display Systems, Avionics.Abstract
Purpose: The design of modern on-board equipment for visualizing air navigation parameters and geodetails (digital district map) is
concerned with certain requirements to the quality of the visualized information to be displayed. This kind of quality may be characterized quantatively in terms of brightness contrast for each color displayed on the screen. To provide stable readability of the image for the pilot, a special procedure should choose chromaticity coordinates of the image elements. The purpose of this research is determining the principles of choosing chromaticity coordinates for the pixels composing the image displayed on the screen. Methods: To visualize the air navigation metrics and geodetails, Multi-Functional Display Units on flat LC panels are used in on-board aircraft equipment. The choice of chromaticity coordinates of the image elements aims to obtain the maximum value of brightness contrast in every presumed color. The calculation of the chromaticity coordinates was based on Maxwell’s color mixing triangle by mutual transformations between elements of ХY-plane and decimal codes of RGB-palette, used in the software of the on-board indication equipment. Numerical values of (x,y)-chromaticity coordinates used for the indication of the air navigation data (one set of colors) and geodetails (another set of colours) were obtained. Results: The idea of the research was to perform a series of experimental measurements of brightness contrast for images displayed in various colors under external illuminance of various levels up to 75 klx, produced by a special lighting unit. Samples of MFDU with mounted screens and gas discharge tubes of sublight made by various manufacturers (SEXTANT, NEC, SIEMENS, SHARP) were tested. Quantative estimations of brightness contrast in different colors are shown in charts. The decision-making rule approving the use of RGB-codes is the case when the brightness contrast of the test image displayed in any predefined color exceeds two. Practical relevance: The results of the research were obtained during experimental design works and can be used by indication equipment software developers to choose chromaticity coordinates providing stable visual perception under high external illuminance.