catrueeb
Posts: 5
Joined: Wed May 15, 2019 7:44 am

IMX219 Camera Very Strong Color Band Flickering

Wed May 15, 2019 8:06 am

Hi All

Could you quickly check out the short video I uploaded to youtube and tell me if you have seen something like that before?
https://www.youtube.com/watch?v=P1tCDYNkpYk

I bought a couple of IMX219 sensor cameras for the use with the rasperry pi camera board from waveshare (https://www.waveshare.com/product/mini- ... 19-d77.htm). When recording, videos are continuously flickering colorbands across the screen, especially when the lighting changes.
I tried different resolutions, framerates, shutter speeds and buffer depths. Also I tried three different power adapters (Operating in Europe at 50 Hz), but I did not see any improvements yet. I have no Idea where this comes from, might be some interference from other devices?

Help would be appreciated, thanks!

jamesh
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Re: IMX219 Camera Very Strong Color Band Flickering

Wed May 15, 2019 8:29 am

Talked to an expert, he thinks that's a problem with the CSI-2 peripheral losing line sync. Why is the interesting question. You appear to be using a non-standard sensor (long cable). If you use the standard sensor is that any better? If it is I would suspect interference, although very odd the sync is lost in the same place each time.
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catrueeb
Posts: 5
Joined: Wed May 15, 2019 7:44 am

Re: IMX219 Camera Very Strong Color Band Flickering

Wed May 15, 2019 8:38 am

Thank you for the reply! It is like you said, with the standard camera I do not see any flickering or colorbanding, it works fine. Only with the long cable. I guess it would be worth trying to properly shield the connecting cables. Do you know any other ways around this?

jamesh
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Re: IMX219 Camera Very Strong Color Band Flickering

Wed May 15, 2019 9:03 am

Cannot think of anything but trying shielding.
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6by9
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Re: IMX219 Camera Very Strong Color Band Flickering

Wed May 15, 2019 11:26 am

That is almost certainly CSI corruption.
If an image line gets dropped due to too many bit errors then the Bayer order is corrupted. Greens get treated as red/blue, and red/blue gets treated as green, therefore colours tend to shift to a purple/magenta.

CSI2 is designed for interconnects of a few cm, not long lengths. The flexi cable between the Pi and camera board isn't perfectly impedance matched, but has done what is possible to reduce cross talk. The pinout from the camera board to the sensor retains that to some degree, but it's unknown as to how Waveshare have routed it from the connector to their flexi. That flexi also has the unbalanced main clock signal for the sensor, therefore it's going to be radiating like anything at 24-25MHz.
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HermannSW
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Re: IMX219 Camera Very Strong Color Band Flickering

Wed May 15, 2019 11:38 am

I bought a similar cheap replacement camera on aliexpress, no issues with that, but 6by9 warned in that thread as well:
"Cheap repair replacement for v2 camera sensor, v2 board must be intact"
https://www.raspberrypi.org/forums/view ... 3&t=231095
bookmark list: https://stamm-wilbrandt.de/en/Raspberry_camera.html

https://github.com/Hermann-SW/Raspberry_v1_camera_global_external_shutter
https://github.com/Hermann-SW/fork-raspiraw
https://github.com/Hermann-SW/userland
https://twitter.com/HermannSW

catrueeb
Posts: 5
Joined: Wed May 15, 2019 7:44 am

Re: IMX219 Camera Very Strong Color Band Flickering

Wed May 15, 2019 4:14 pm

HermannSW wrote:
Wed May 15, 2019 11:38 am
I bought a similar cheap replacement camera on aliexpress, no issues with that, but 6by9 warned in that thread as well:
"Cheap repair replacement for v2 camera sensor, v2 board must be intact"
https://www.raspberrypi.org/forums/view ... 3&t=231095
That is weird... I have tried out four different cameras and three different V2 boards and I am having this issue everytime. I guess your camera also has a 80 mm connecting cable to the camera module? I am guessing it is something related to interference / crosstalking or also the power supply, resulting in the CSI corruption. I will report my results then after shielding the connector cables

HermannSW
Posts: 1219
Joined: Fri Jul 22, 2016 9:09 pm

Re: IMX219 Camera Very Strong Color Band Flickering

Wed May 15, 2019 8:41 pm

Yes, 80mm, and official Raspberry 5.1V/2.5A power supply. I have to say that I use 1m long ribbon cables to connect the camera board instead of the 15cm cables, and have no issues. 6by9 always states that anything above 15cm is problematic, but even the 2m ribbon cable works for me if I need the camera far away from the Pi:
Image
bookmark list: https://stamm-wilbrandt.de/en/Raspberry_camera.html

https://github.com/Hermann-SW/Raspberry_v1_camera_global_external_shutter
https://github.com/Hermann-SW/fork-raspiraw
https://github.com/Hermann-SW/userland
https://twitter.com/HermannSW

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