Effects of PWM Dimming LED Illumination on Camera Images and Countermeasures

Abstract

This paper presents the analysis of brightness fluctuation for camera images under the PWM dimming LED Illumination environment and countermeasures against it. The exposure dose of a camera, which depends on PWM frequency and duty, exposure time and shooting instant of a camera, and video frame rate, was analyzed using a computer simulation program. As a result, it was found that the brightness fluctuation did not occur in most cases when the PWM frequency of LED lighting was at a frequency of 24 kHz or its multiple. The experimental results confirmed the effectiveness of proposed brightness fluctuation prevention measures.