Recommended calibration target and procedure for accurate two-ZED 2i point-cloud registration

Hi Stereolabs team,

I came across this discussion where it was mentioned that the ArUco-based multi-camera calibration approach may provide better accuracy for static-object point-cloud applications than ZED360.

I am working with two ZED 2i cameras and my goal is accurate extrinsic calibration for registering their point clouds into a common coordinate system.

Before setting up the calibration, I would like to clarify a few things:

  • For this use case, do you currently recommend ArUco, ChArUco, checkerboard, or another calibration target ?
  • If using ArUco, is there a recommended target size ? For example, would a 500–700 mm marker be sufficient, or would you recommend a larger target for cameras several meters apart?
  • Should I use one large rigid target and move it through different positions, heights, distances, and orientations within the overlapping FOV?
  • Approximately how many target positions/views would you recommend for a reliable calibration?
  • Should calibration always be performed with the cameras in their final mounting positions and orientations ?
  • If I later change the position or angle of either camera, should I perform the complete extrinsic calibration again?
  • What is the recommended way to validate the accuracy of the resulting transformation , particularly for 3D point-cloud alignment?
  • Is the current zed-aruco/multi-camera workflow still the recommended approach with the latest ZED SDK 5.x?

My main requirement is accurate 3D point-cloud registration , rather than only object/body tracking through Fusion.

Any recommendations regarding the target type, target dimensions, calibration procedure, and validation method would be greatly appreciated.

Thank you!