The Visibility Level Calculator (VLC) Application:

Diminished visibility in dim light degrades performance and safety on tasks that depend on the timely detection of visual targets. Various contrast-detection models have been proposed to quantify visibility in dim light. Of these, the Adrian (1989) visibility level (VL) model accounts for more of the important variables (e.g., target size, distance and luminance, background luminance, target distance, viewing duration, observer age, glare illuminance and location, and eye colour) and is the most widely accepted. The visibility level calculator (VLC) provides engineers, human factors professionals and vision scientists with a free easy-to-use tool that automates the calculation of VL within the modified Adrian/CIE model (Ising, 2008).

Several target and observer factors that affect visibility that are not currently included in the Adrian/CIE model provide significant opportunities for future research to enhance the measurement of nighttime target visibility. We hope that the VLC will foster lab and field studies to advance the Adrian/CIE model and enhance the objective measurement of VL.

Nighttime visibility, safety in nighttime driving, the modified Adrian/CIE model, the calculation steps in and guidelines for using the VLC and future research suggestions are provided in a paper currently in press at Journal of Science and Technology in Lighting.

References [1] Adrian, W. (1989). Visibility of targets: Model for calculation. Lighting Research and Technology, 21(4), 181-188. [2] Ising, K. W. (2008). Threshold visibility levels required for nighttime pedestrian detection in a modified Adrian/CIE visibility model. LEUKOS: Journal of Illuminating Engineering Society of North America, 5(1), 63-75.

The VLC was created by Adrienne, Donald & Theresa Kline The University of Calgary December, 2019