April Tag + RGBD

MarilleTielens

I would like to track a marker like an April tag from far distances, so using the color cam with a high resolution and having the detection running on the camera using the april tag node would be great. However, the example in the documentation is only for detection and not tracking. I assume using something like the imageAlign node or RGBD node would be the next step. Unfortunately I don't really understand how I should do this. I would appreciate some advice or examples.

Oskar-Luxonis

Hey MarilleTielens - AprilTag detection already gives you the tag ID and corner coordinates on every frame, so you can use the ID to track the same marker over time.

If you also need its distance/3D position, align the stereo depth to the RGB stream and then sample the aligned depth at the tag center (or a small region inside it). StereoDepth/Depth alignment is the preferred path; ImageAlign is useful for more general alignment cases.

The 12MP AprilTag example is a good starting point: https://docs.luxonis.com/software-v3/depthai/examples/april_tags/april_tags_12mp/

If you use a coding agent, Luxonis Agent Skills can help create a working proof of concept: npx skills@latest add luxonis/skills, then use luxonis-build-poc.

Thanks,
Oskar