Visual Performance under Varying Illumination Conditions while using an Indigenously Developed Wrist Wearable Computer

Abstract

Ambient illumination conditions have significant impact on users’ visual performance while carrying out onscreen reading tasks on visual display units, especially smaller screen sizes. Present study assessed the visual performance responses of different ambient illumination levels during onscreen reading on Wrist Wearable Computer (WWC) developed for the command-control-communication between the control room and the soldiers operating in remote locations. Ten (10) Indian Infantry soldiers performed two different types of loud reading tasks on the display of WWC under three different ambient illumination (mean ±SEM) conditions namely, Indoor controlled (450.00±10.00 lx), Outdoor daylight (11818.7±582.91 lx) and Indoor dark (0.12±0.03 lx) environments. While reading, participants wore an eye tracking glass which recorded the eye movement responses. Visualisation techniques were used to predict the association of illumination levelof surrounding with visual performance of the user. Subjective legibility rating was also applied to understand participants’ preferences towards physical attributes of the onscreen information and illumination level. Results indicated that illumination had a significant effect on eye movement parameters like fixation frequency, fixation duration and scanpath length while completing the tasks. Overall, participants performed better under indoor controlled illumination conditions in terms of fixation profile and scanpath length, apart from improved subjective legibility ratings as compared to other two illumination conditions. Future research attempts need to be directed towards the optimum performance of the display across wide range of ambient illumination conditions and to establish how the display of indigenously developed wearable computer performs in comparison to other such displays available across the globe.