ZED 2i: Severe magenta/purple image corruption after bright sunlight exposure

Hardware ZED2
1

Key observations:

  • The issue has been observed on a large number of cameras. We have nearly 200 ZED 2i units deployed, so this does not appear to be a failure of a single camera.

  • I have observed this issue using both SDK 4.x and zed-open-capture.

  • A previous employee discussed this with Stereolabs support and was reportedly told that the camera must be power-cycled when the issue occurs.

  • Power-cycling is not an acceptable solution for our application because we cannot experience random interruptions during operation.

  • The issue has only been observed outdoors in bright sunlight. I have not yet been able to reproduce it indoors.

  • The camera may operate normally for extended periods (for example, more than an hour) before the issue occurs or it can occur within seconds of turning on.

  • In at least one case, the issue appeared immediately after the camera was turned toward the sun while being moved/stored.

  • The corrupted image is not simply overexposed. Bright regions become white, but many highlight transitions and reflective surfaces develop strong magenta/purple coloration.

  • The issue can affect large portions of the image and produces unusable data for computer vision.

Current configuration:

  • Using zed-open-capture.

  • Camera hardware AEC/AGC disabled.

  • Running a custom software exposure/gain control loop.

  • Camera white balance control disabled.

  • Disabling white balance may have reduced the frequency of the issue but has not eliminated it.

Additional observations:

  • The open-capture source appears to indicate an OV580 ISP/bridge and OV4689 image sensors.

  • The project includes logging of OV580 ISP registers and OV4689 exposure/gain registers, suggesting there may be ISP state related to this issue.

  • Because the problem has been observed with both the SDK and open-capture, I suspect the issue may exist below the application layer.

Questions:

  1. Is this a known issue with the OV580/OV4689 image pipeline used in the ZED 2i?

  2. What internal camera state is becoming corrupted when this occurs?

  3. Is there a documented recovery method that does not require a USB power cycle?

  4. Are there specific ISP, AEC/AGC, AWB, or OV580 configuration registers that should be disabled or initialized differently to prevent this condition?

  5. Has Stereolabs identified the root cause or a mitigation for deployments operating continuously in bright outdoor environments?

Any guidance would be appreciated.

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2

Hi @dweinlader
Welcome to the StereoLabs community.

What you described is a rare problem caused by a rare combination of factors (mostly outdoors) that cause the overflow of one of the registers of the OV580.
Regrettably, the only working solution is to call the reboot function to force a reset of the camera registers because a simple rewrite of the affected register does not fix the issue.

The reboot command is sent to the MCU of the ZED 2i, which forces a reset of the OV580. This operation is the same as disconnecting and reconnecting the USB plug.

3

Thank you. I will try that. Is this something you might consider fixing with a firmware update for the camera?

4

Yes, the hardware team is analyzing and trying to fix it.