NVIDIA Corporation
Detecting flicker bands using multi-exposure sensors

Abstract:

Alternating Current (AC) light sources can cause images captured using a rolling shutter to include alternating darker and brighter regions--known as flicker bands--due to some sensor rows being exposed to different intensities of light than others. Flicker bands may be compensated for by extracting them from images that are captured using exposures that at least partially overlap in time. Due to the overlap, the images may be subtracted from each other so that scene content substantially cancels out, leaving behind flicker bands. The images may be for a same frame captured by at least one sensor, such as different exposures for a frame. For example, the images used to extract flicker bands may be captured using different exposure times that share a common start time, such as using a multi-exposure sensor where light values are read out at different times during light integration. Two or more images captured for a frame may be used for flicker band extraction, such as the two images that include flicker bands with the greatest phase difference.