Checkerboard targets, spheres and manually set points can currently be used to register scans. A useful extension would be the use of AprilTag Targets. The advantage of AprilTag Targets is their uniqueness, similar to a QR code. Thus, the automatic registration of scans could be improved since the targets are automatically identified immediately. You can download examples of April Targets here: https://www.dotproduct3d.com/targets.html