Preliminary Design of an Image Quality Tester For Helmet-Mounted Displays

摘要

Helmet-mounted displays (HMDs) provide essential pilotage and fire control imagery information for pilots. However, image quality testers for HMD field performance validation do not currently exist. This research employed techniques from imaging analysis and interpretation, and computer-aided design/ computer-aided manufacturing (CAD/CAM) to investigate a preliminary design for a portable HMD image tester. For this study, a charged couple device (CCD) camera and lens were selected. Hardware characteristics such as viewing angles in horizontal and vertical positions, dynamic working range at day and night, pixel resolution, focal length, and aperture ratio were evaluated with regard to HMD functionality. Experiments to evaluate camera sensitivity and test pattern merits were conducted using a programmable micro positioning system, CCD camera, optical fixtures and benches. Next, the relative ratio among features within the image profile was established and an ideal image profile and evaluation criteria were established based on the experimental results. Third, image processing algorithms and techniques, such as edge detection, were developed and applied in test pattern feature.