Detection of stroboscopic effects in dependence of duty cycle, speed and illuminance level

Light-emitting diodes (LEDs) that are dimmed by pulse width modulation (PWM) may cause visually uncomfortable stroboscopic effects due to improper selection of operating parameters. Therefore, it is important to understand that the visibility of the stroboscopic effect depends on parameters such as duty cycle, speed, and illuminance level.
These dependencies were analysed by using a LED light source illuminating a black-coated rotating disk with a white dot mounted on top of it. Modulating the light source with a square wave signal between 100 Hz and 4200 Hz and different duty cycles (10%, 30%, 50%, 70%, 80%), allowed us to determine the subject’s visibility of the stroboscopic effect for different rotation speeds (2m/s, 4m/s, 6m/s) and illuminance levels (100lx, 500lx, 1000lx).
Based on the results of these experiments, objective models were developed, which can be used to increase the accuracy and validity of the stroboscopic visibility measure, and effectively reduce the stroboscopic effects.