High-dynamic imaging system for real-time detection of illuminance by vehicle head lamps

In this paper, we propose an imaging system for quick detection of high-dynamic illumination with a high-contrast cutoff line. A digital camera is used to capture the image of the light pattern from a vehicle headlamp. After having image processing and calibration, we can accurately obtain the illuminance of the measurement plane while different exposure times are used to increase the dynamic range of the system measurement. Two representative regulations are mainly discussed, one is K-mark and the other is ECE R113 Class B. Results show that the measurement errors of our imaging system are within ±5% when the values are more than 2 lx, and have a difference of 0.1 lx when the values are less than 2 lx.