A Limited Rotary-Wing Flight Investigation of Hyperstereo in Helmet-Mounted Display Designs

A number of currently proposed helmet-mounted display (HMD) designs relocate image intensification (I2) tubes to the sides of the helmet. Such a design approach induces a visual condition referred to as hyperstereo vision (or hyperstereopsis). This condition manifests itself to the user as an exaggerated sense of depth perception, causing near- to mid-range objects to appear closer than they actually are. Hyperstereopsis is potentially a major concern for helicopter operations that are conducted at low altitudes. As part of a limited flight study to investigate this phenomenon, five rated U.S. Army aviators, as technical observers (hands-off-the-controls), wore a hyperstereo HMD during the conduct of a series of 13 standard maneuvers. Two subject aviators acquired a total of eight hours and three aviators a single hour of flight. Using a post-flight questionnaire, these aviators were asked to compare their visual experiences to that of normal I2-aided flight. Depth perception at distances below 300 feet was identified as the greatest challenge. The two 8-hour aviators reported a 5-8 hour adaptation period for most maneuvers. The original document contains color images.