The Human Factors of Night Vision Goggles

Abstract

The technology underlying night vision goggles (NVGs) enhances human ability to operate in dark and low-light conditions. However, NVG-aided vision is limited relative to daylight human vision and may entail risks. This review focuses on NVGs with image intensifier technology and explores the impact of their use on human performance. The review covers technology and device characteristics (image quality and field of view), physical configuration (ocular configuration, NVG weight, and forward center of gravity), and contextual and environmental factors (mission and task aspects, lighting, weather, and terrain). The key human factors in NVG use are visual and cognitive performance (visual acuity and contrast sensitivity, stereopsis and depth perception, distance and size estimation, spatial orientation, and situation awareness), and physical and physiological aspects (neck strain and injuries, and headaches). Understanding technology and contextual factors and their influence on human factors is critical to improving performance and safety with NVGs. Technology and device improvements, along with appropriate mission planning and training, play a critical role in aided night vision performance. INTroDuCTIoN Vision is the most dominant perceptual sense and requires adequate lighting to be effective. Yet there is often a need to operate in inadequate lighting circumstances. Many military missions and tasks are performed in poor light conditions and in the dark because it affords better concealment and surprise. In addition, numerous civilian operations and occupations take place in poor lighting conditions: search and rescue, law enforcement (police, border control, surveillance, etc.), hunting, wildlife observation, and many more. In most of those circumstances, people aim to perform in poor light conditions as well as they would in the daytime. However, although humans have developed exceptional day vision, they nevertheless have poor night vision. There is a real need, therefore, for technologies to enhance vision in low-light circumstances.

Metabolic Demands and Kinematics During Level Walking in Darkness With No Vision or With Visual Aid

“…Since usage of NVG entails good foveal visual input but causes loss of peripheral visual cues, the results indicate that mechanical efficiency is affected by loss of peripheral vision. Both the Mono and the Bino NVG restrict the visual field to 40°, 14 , 15 , 17 suggesting that optimization of mechanical efficiency requires a visual field exceeding 40°. It cannot be excluded that other characteristics of the NVG images may have impaired spatial orientation and/or balance and therefore prevented an optimization of the mechanical efficiency.…”

“…Individuals engaged in foot-borne operations in complete darkness are typically personnel from the uniformed services that undertake surveillance, security, and rescue operations, while using visual aid in terms of night vision goggles (NVG). Since NVG devices markedly limit the peripheral visual field, 14 , 15 and hence the optical flow, 16 that may impact the foot trajectory during walking, 10 we reasoned that it would be of interest to evaluate the metabolic demand during walking at moderate speed in darkness with NVG.…”

Basics of sensation and perception with an eye toward application.

“…Limits of the field of view are relevant when designing technologies to aid vision, or when arranging multiple displays that must be monitored by a single user. For example, most night-vision goggles typically limit the field of view to between 30° and 45°, which requires operators to make more head movements to scan the environment and thus can increase fatigue and cognitive workload (Parush, Gauthier, Arseneau, & Tang, 2011).…”