Estimation and correction of geometric distortion of stroke-based symbology for avionics display system using curve fitting

Abstract

High-precision avionics display system like head-up display (HUD) are used to display the flight information of several selectable modes in the collimated form so that the pilot can view this information superimposed on his view of the outside world without changing his line of sight or visual accommodation. The information display symbology formed on the HUD is governed by the horizontal and vertical deflection signals as per the X-and Y-coordinates of the reticles which are synchronised with the blanking signal. Being an electro-opto-mechanical display, these displays are prone to the geometric distortions. This research work aims at establishing high positional accuracy of the display symbology by using a geometric distortion correction system (DCS) for stroke-based avionics display system based on curve fitting. The rectification is applied to images of three different HUDs, with respect to their placement of reticles, aiming to test residuals in X-and Y-axes. The developed system features simple approach, cheap expenses, high accuracy and its capability to provide real-time and accurate coordinates of the image displayed on the HUD.