improvment of Zed X 2.2mm in no light scenaios

Hardware ZED X
1

Hey everyone,

I’m currently developing an autonomous UGV intended primarily for nighttime and low/zero-light operations. I’m using a Stereolabs ZED X (2.2mm wide-angle lens) as the primary vision sensor for depth estimation and VIO/SLAM.

Because the ZED X is a passive stereo camera, performance in total darkness is a major concern due to feature starvation and high sensor noise from auto-exposure gain.

I’m evaluating the best hardware setup to make passive stereo viable in complete darkness and would love your input on two main options:

  1. Active Texture / Pseudo-Random Pattern Projector (NIR / 850nm or 940nm):

    • Pros: Projects structured texture onto featureless walls/ground for disparity matching without visible glare.

    • Concerns: The ZED X has an integrated IR-cut filter and standard RGB Bayer sensor (unless using an IR version), so NIR pass-through might be weak. Also, FOV coverage with a 2.2mm ultra-wide lens (~110°+ HFOV) and maximum effective range outdoors might be limited.

  2. Visible LED Floodlights / Diffused Spot Illumination:

    • Pros: Direct compatibility with the RGB sensor, maximizes feature tracking for VIO/SLAM pipelines.

    • Concerns: High power draw on the UGV battery, potential backscatter/glare from dust/fog, and visible light signature if stealth is desired.

Questions for the community:

  • Has anyone successfully run passive stereo / ZED X in pitch-black outdoor conditions? What illumination setup worked best for you?

  • If using a pattern projector, did you need external synchronization/strobing to avoid motion blur or frame-rate drops?

  • Does a high-CRI diffused LED floodlight perform better than structured light once range exceeds 5–10 meters on a wide-angle lens?

  • Are there alternative sensor-fusion approaches you’d recommend (e.g., thermal stereo, 2D/3D LiDAR assist, or IMU-heavy VIO tuning) for dark environments?

Any advice, hardware recommendations, or lessons learned would be greatly appreciated!

Thanks in advance!

2

@Myzhar hey could you please help me with the above mentioned problem.

3

Hi @Jai
Welcome to the StereoLabs community.

This is a challenging operating conditions for our cameras because they do not have active projectors. Passive stereo vision requires visual features to extract depth information, even when using AI.

This is the point.

This is not feasible. All the ZED cameras are provided with IR filters to avoid sunlight saturation (reddish image issue), so these frequencies of IR light are blocked.

This is the only working solution. We recommend using diffused light, not spot light.

Customers working in full dark conditions use diffused LED ligths.
It’s important that the FoV of the camera is homogeneously illuminated to not create unwanted depth artifacts.

This is a good practice. ZED Link capture cards provide strobo signals:

This performs better in any case.