Are All Aruco Markers Unique?

From what I understand, Aruco marker range from 0-999.

I would imagine all are unique, but for sanity purpose I would like to know from the community:

Are any of those markers re-used but at a different orientation.

For example could marker x be the same pattern as marker y, but marker y is rotated 90 degrees?

I feel like this is impossible since aruco markers can be recognized by opencv in any rotation, but just want to double check.

Thank you.

this type of marker (also ARToolKit, April, …) is always designed to decode robustly, and it often contains redundancy that allows decoding under some occlusion (assuming detection succeeded) or partially destroyed patterns.

you have nothing to worry about. there are no IDs that “collide”, not even by chance. it’s not a “hash” situation. it contains “coding theory”.


Excellent, thank you!