What is the cause of Z-axis resolution artifacts for structured light 3D cameras?

[pauljurczak]

I’m capturing point clouds with Orbbec Astra Mini structured light 3D camera (similar to this one https://www.orbbec.com/products/structu ... -mini-pro/) and I noticed that Z value resolution is pretty coarse at longer distances. For example, at ~2.6m distance to a flat target, the resolution is about 28mm, i.e. I’m getting these points:

[-123.9576 -187.60762 2682. ]
[-118.79163 -187.60762 2682. ]
[-113.625656 -187.60762 2682. ]
[-108.45967 -187.60762 2682. ]
[ 51.146034 -185.649 2654. ]
[ 56.25808 -185.649 2654. ]
[ 61.37012 -185.649 2654. ]
[ 66.48217 -185.649 2654. ]

and no points with Z coordinates between 2654 and 2682. Is this normal? Why Z values are integral with gaps increasing proportionally to target distance. I understand why the accuracy will decrease with target distance, but integral values are surprising. Do you get similar artifacts with other 3D cameras?

Cross-posted from https://3dclub.orbbec3d.com/t/astra-min ... value/4596 and https://robotics.stackexchange.com/posts/118163.