Simulating Visual Contrast Reduction during Nighttime Glare Situations on Conventional Displays

Bright glare in nighttime situations strongly decreases human contrast perception. Nighttime simulations therefore require a way to realistically depict contrast perception of the user. Due to the limited luminance of popular as well as specialized high-dynamic range displays, physical adaptation of the human eye cannot yet be replicated in a physically correct manner in a simulation environment. To overcome this limitation, we propose a method to emulate the adaptation in nighttime glare situations using a perception-based model. We implemented a postprocessing tone mapping algorithm that simulates the corresponding contrast reduction effect for a night-driving simulation with glares from oncoming vehicles headlights. During glare, tone mapping reduces image contrast in accordance with the incident veiling luminance. As the glare expires, the contrast starts to normalize smoothly over time. The conversion of glare parameters and elapsed time into image contrast during the readaptation phase is based on extensive user studies carried out first in a controlled laboratory setup. Additional user studies have then been conducted in field tests to ensure validity of the derived time-dependent tone-mapping function and to verify transferability onto real-world traffic scenarios.