Abstract

The flight simulation training industry has considered the use of stereoscopic, or 3D, displays for decades, yet their use is still limited to a small fraction of training applications. Primary reasons for their slow adoption include high cost and complexity, discomfort, and the belief stereopsis is not useful at distances greater than about 10 m. The cost and complexity of 3D displays is rapidly declining due to heavy investments by other industries, minimizing this barrier to their use in flight simulation. The barriers of discomfort and working distance are addressed in this paper. An evaluation of standard and 3D display systems designed for air refueling boom operator training was conducted with operators estimating the distance between receiver aircraft and the boom nozzle. Relative distance estimates were significantly more precise for the 3D condition, even at the 20 to 25 working distance of the boom operators. This finding is at odds with the findings of researchers who concluded stereopsis is of little use at this distance, but who used low resolution displays in their evaluations. An evaluation of spatial resolution and antialiasing was conducted that showed stereoacuity thresholds as low as 5 to 10 arcsec are attainable. For antialiasing kernel widths less than about 1.2 pixels, both stereoacuity and comfort are heavily dependent on display pitch over the range of 0.5 to 3.5 arcmin. For kernel widths greater than about 1.6 pixels, display pitch had a much smaller effect on stereoacuity and comfort. These results suggest stereoscopic displays have been undervalued by previous researchers due to the low resolution and insufficient antialiasing used in their evaluations. The results imply appropriately designed 3D displays are more useful than previously thought for air refueling and rotary wing tasks involving working distances of up to 25 m.