ZED X Mini Pulsating Depth During Motion

Software
1

Hello,

We’ve been using ZED X Mini cameras on our robot for perception, including depth estimation. Recently we began noticing that the depth data pulsates significantly when the robot is in motion, making the depth practically unusable. We’ve tested using all three NEURAL depth modes and various levels of depth stabilization, but nothing has resolved the issue.

Here’s a .svo2 file which shows the issue when played back using the ZED Depth Viewer: pulsating_depth_zed_x_mini.svo2

Please let us know what the issue may be, and how it can be fixed.

Thank you!

2

Hi @TomaszTB
Welcome to the Stereolabs community.

What ZED SDK version are you using?
Please provide more information concerning your setup.

3

Hello @Myzhar

We’re currently using ZED SDK 5.1.2, and we interface with the camera using the ZED C API (from the 5.1 release, in case that matters).
The ZED X Mini in the SVO is mounted on the humanoid robot’s torso, angled down to see the terrain. We have another ZED X Mini in the head, which experiences the same depth quality issue. I can find an SVO from the head camera’s perspective as well if it’s necessary. They’re both connected to a Jetson AGX Orin.

I hope this information helps.

4

It looks like an exposure problem caused by big variations of lights in the scene.

You can try to take two different approaches:

  1. disable automatic exposure
  2. set a Region of Interest for auto exposure in a zone of the image that have little variations
5

Interesting. We’ll try again with fixed exposure and get back to you with the results.

In the meantime, I found an SVO from the head ZED X Mini. The same wobbling/pulsating depth is visible when the robot is in motion. Seems that even slight shakes of the head cause wobbling. I’ve also included a screen recording of what I see in the ZED Depth Viewer, just to be sure we’re looking at the same issue.

SVO file: wobbly_depth_head_zed_x_mini.svo2

Screen recording: wobbly_depth_screen_recording.webm

Does this also look like an exposure variation issue?

6

Are you using Depth Stabilization?
The default value is 30, that is good for dynamic conditions, but in your case the dynamic of the system is very quick, so you could try to lower this value.