Thresholds of perceptual fatigue based on 3D object motion vectors and relative object size in virtual reality

Over the past decade, Virtual Reality (VR) devices have not only emerged on the consumer market, but in various civilian and military use cases as well. One of the most important differences between the typical forms of VR entertainment and utilization in professional contexts is that operation may not be interruptible in case of the latter. For example, while the continuity of spatial surveillance and threat detection is indeed vital to the success and safety of tactical military scenarios, the operator may be affected by perceptual fatigue, particularly after extended periods of VR equipment usage. The same is applicable to both ground and air reconnaissance, as well as piloting and targeting. However, the thresholds of perceptual fatigue are affected by numerous human factors, equipment attributes and content parameters, many of which are not yet addressed by the scientific literature. In this paper, we present our large-scale study on the thresholds of perceptual fatigue for VR visualization. Five levels of fatigue are differentiated in order to examine the correlations between human perceptual endurance and the investigated test conditions in more detail. The experiments distinguish content based on motion vectors and object size relative to the space of perceivable 3D visualization. The majority of the exhaustive tests are analogous to the different zoom levels of visual capture equipment. Therefore, our work highlights optimal device settings to minimize the potential perceptual fatigue, and thus to support longer periods of uninterrupted operation.