Real-Time LED Flicker Detection and Mitigation: Architecture and FPGA-Implementation

Flicker mitigation is an computer vision algorithm class, reducing the amplitude modulation effect of pulsed LED light sources captured with an unsynchronized discrete exposure image sensor. These disturbing effects prevent legal admission for digital side mirror systems in automotive and traffic sign recognition from digital speed limit signs. Based on a bidirectional dense optical flow block matching algorithm between successive frames of a video sequence and a threshold based classification, flicker can be detected and mitigated. In this paper we propose a configurable hardware implementation of the two stage algorithm for FPGAs, for real-time, low-power processing. The proposed architecture is able to mitigate flicker artifacts with a framerate of > 30 fps for a resolution of [ 1280×1088] on a Xilinx Virtex-6 LX240T FPGA.