You mean the black horizontal bands? That'll be mains frequency flicker on a rolling shutter camera.
A rolling shutter camera exposes each line at a slightly different time, as it reads out the line immediately that the exposure completes.
When using fluorescent or other lighting that is actually a flash per mains half cycle, then if the exposure period is not a multiple of the mains half cycle each line will see a slight variation in the amount of illumination from your light source, and you'll see this type of variation in brightness.
If using a long enough exposure time, then adding "--flicker-period 10000" to rpicam-apps when the mains is 50Hz, or "--flicker-period 83333" for 60Hz, will make the AE algorithm use exposures which are an appropriate multiple.
If your exposure time is less than a single half cycle, then there is very little you can do without changing the light source.
See also AeFlickerMode and AeFlickerPeriod in the picamera2 docs.
A rolling shutter camera exposes each line at a slightly different time, as it reads out the line immediately that the exposure completes.
When using fluorescent or other lighting that is actually a flash per mains half cycle, then if the exposure period is not a multiple of the mains half cycle each line will see a slight variation in the amount of illumination from your light source, and you'll see this type of variation in brightness.
If using a long enough exposure time, then adding "--flicker-period 10000" to rpicam-apps when the mains is 50Hz, or "--flicker-period 83333" for 60Hz, will make the AE algorithm use exposures which are an appropriate multiple.
If your exposure time is less than a single half cycle, then there is very little you can do without changing the light source.
See also AeFlickerMode and AeFlickerPeriod in the picamera2 docs.
Statistics: Posted by 6by9 — Tue Apr 23, 2024 1:44 pm