Frequency out-of-sync grey bands on captured images
gns-jdaniel opened this issue · comments
Is there any way to add an option to add an anti-flicker adjustment for capturing still images? The photos I'm getting under these 60 Hz grow lights have rolling horizontal grey bands on them.
See attached samples...
Hey @gns-jdaniel ,
Unfortunately, it seems that there is no "--flicker" setting available in the libcamera apps, and I couldn't find a replacement for it when using libcamera-still to capture images. This has also been mentioned in the "Differences compared to raspicam" section of the raspberrypi documentation.
I came across an open issue on the libcamera-apps Github repository that addresses this problem and it might be worth checking the raspberrypi forum to see if anyone has found a workaround for this issue.
If we can find a setting for libcamera-still, I can try adding it to the Raspicam app. Let me know if you have any suggestions or insights on this matter.
In the previous thread, you mentioned that flicker can be reduced by not using the timelapse function. I was wondering if you could test this with the new version and share your results?
Unfortunately, I can't do anything until libcamera re-adds the flicker setting.
This setting?
extern const std::array<const ControlValue, 2> [LensShadingMapModeValues](https://libcamera.org/api-html/namespacelibcamera_1_1controls_1_1draft.html#aa16e02d987ec168b4d910a6e30a5aa79); extern const [Control<int32_t>](https://libcamera.org/api-html/classlibcamera_1_1Control.html) [LensShadingMapMode](https://libcamera.org/api-html/namespacelibcamera_1_1controls_1_1draft.html#a0849d24af45ddc950e44637abc7c0e01); enum [SceneFlickerEnum](https://libcamera.org/api-html/namespacelibcamera_1_1controls_1_1draft.html#a97800fb1d3afef07eb550873af0dbe16) { [SceneFickerOff](https://libcamera.org/api-html/namespacelibcamera_1_1controls_1_1draft.html#a97800fb1d3afef07eb550873af0dbe16ae1ba6904ca34f985055ad682a7fafb10) = 0, [SceneFicker50Hz](https://libcamera.org/api-html/namespacelibcamera_1_1controls_1_1draft.html#a97800fb1d3afef07eb550873af0dbe16a47ff793173200c8e77e95cc5aa3cfb8d) = 1, [SceneFicker60Hz](https://libcamera.org/api-html/namespacelibcamera_1_1controls_1_1draft.html#a97800fb1d3afef07eb550873af0dbe16aee10a6ec1f8e8ba14d3977c34a996850) = 2, };
I'm using the libcamea-still command line tool. Maybe this settings are only internal used? Can you try to call libcamera-still with the flicker setting on the command line?
In the Raspberry pi documtation they also mention they don't support this setting in libcamera apps
https://www.raspberrypi.com/documentation/computers/camera_software.html#differences-compared-to-raspicam-apps
"There is no support for setting the flicker period yet."
I will try to update my system and check if there is a setting for it.
I've been playing with the --shutter setting, in hopes of finding an ideal value in microseconds that matches my 60Hz lighting.
This is what my camera is capable of:
`$ libcamera-still --list-cameras
Available cameras
0 : imx708 [4608x2592] (/base/soc/i2c0mux/i2c@1/imx708@1a)
Modes: 'SRGGB10_CSI2P' : 1536x864 [120.13 fps - (768, 432)/3072x1728 crop]
2304x1296 [56.03 fps - (0, 0)/4608x2592 crop]
4608x2592 [14.35 fps - (0, 0)/4608x2592 crop]`
If I use a command like this:
libcamera-still --hdr --rotation 180 --sharpness 0 --brightness 0 --ev 0 --gain 0 --metering average --exposure normal --awb auto --lens-position 4.6 --nopreview --quality 80 --width 4056 --height 3040 --timeout 2000 --thumb 320:240:35 --shutter 25000 --output test-25000ms-01.jpg
where I find some magical value for --shutter...do you think this will work?
AND in case anyone reading this can assist...any idea what a good value would be? 14.35fps/60Hz = 239166 microseconds, so I've obviously done my math wrong...but am I on the right track? Do you think I can find a reasonable value for shutter that will deliver a flicker-free image?