GMSL Camera blue-purple artifacts strategy

Autonomous Vehicles DRIVE AGX Xavier DRIVE AGX Xavier General
1

When we capture/record a video with the sample code …
./sample_camera_gmsl
… blue-purple artifacts appear on frame. According to the answers on forum, the effect is caused by Auto Exposure on cameras.

  • Auto exposure effect is less when we run ./sample_camera_gmsl_raw.

  • Auto exposure effect does not occur when we record with USB camera. However, when we capture with USB Camera latency is much higher and quality is much lower than GMSL.

Firstly, I would like to know what changes when we change the output type.
Secondly, I’d like to know what causes the difference in between GMSL camera and USB camera (latency, quality and artifacts.)
Finally, I would like to get some advices on how to solve the auto exposure issue.

Thank you in advance,

2

Dear ocakirog,

Could you please refer to DriveWorks Image Signal Processing (ISP) section in DriveWorks docs for this topic? Thanks.
DriveWorks SDK Reference → Development Guide → Sensor Abtraction Layer → ISP

3

So what is the solution to the purple artifacts problem?

4

Dear @sleff,
Inside office premises, purple color artifcats are expected when moving camera. It happens around the areas of the image with sharp brighness change and quick movement. Please check in outside premises and see if you face any issue

5

Thanks @SivaRamaKrishnaNV. That explains when the purple artifacts happen. But it doesn’t explain why they happen. I’ve not seen this type of artifact on other cameras before.

6

Hi @SivaRamaKrishnaNV any more info on what causes this trailing purple effect? Is it caused by the image sensor or ISP? And if it causes by the ISP, what is driving this artifact? Auto Exposure? Over exposure correction?

I find it interesting that this artifact is most apparent with movement. This makes me think that the ISP is using multiple frames to account for over exposed areas.

Thanks,
Daniel

7

Hi @danielz6ppg,

Please refer to my reply in another topic. Thanks!

8

I dont understand the relevance of that thread. Unless you are saying that simultaneous LFM and HDR is causing the artifact.

I should clarify that I am seeing this issue on the AR0820.

Daniel

9

Hi @danielz6ppg,

If it’s on AR0820, are you using DRIVE Software 10.0? Did you get the drivers from the vendor? Have you checked with them? For further discussing in forum, please create another topic. Thanks!