Improving Registration Quality

[sSeLeMaHs]

Hi Guys,

In the past couple of weeks i tried to build and run a low cost mobile laserscanning device. I use a Livox Mid360 and a Jetson Orin Nano. In easy scenarios (a hole floor of several rooms) i get pretty good results with Glim compared to a precise Leica RTC360 scanner.

Now i tried to scan a long and narrow supply corridor, which is around 150 m long. I tried several configurations of the Odometry-, Submap- and Global Mapping Parameters, but i still see a pretty big drift in height. My current parameters are as follows:

{ "odometry_estimation": { "fix_imu_bias": false, "full_connection_window_size": 2, "init_pose_damping_scale": 10000000000.0, "initialization_mode": "LOOSE", "initialization_window_size": 1.0, "isam2_relinearize_skip": 1, "isam2_relinearize_thresh": 0.1, "keyframe_delta_rot": 0.25, "keyframe_delta_trans": 1.0, "keyframe_entropy_thresh": 0.99, "keyframe_max_overlap": 0.7, "keyframe_min_overlap": 0.01, "keyframe_update_strategy": "OVERLAP", "max_num_keyframes": 15, "num_threads": 2, "save_imu_rate_trajectory": true, "smoother_lag": 10.0, "so_name": "libodometry_estimation_gpu.so", "use_isam2_dogleg": false, "voxel_resolution": 0.05, "voxel_resolution_dmax": 20.0, "voxel_resolution_dmin": 5.0, "voxel_resolution_max": 0.5, "voxelmap_levels": 2, "voxelmap_scaling_factor": 2.0 } }

{ "sub_mapping": { "between_registration_type": "GICP", "create_between_factors": true, "enable_imu": true, "enable_optimization": false, "keyframe_randomsampling_rate": 1.0, "keyframe_update_interval_rot": 0.5, "keyframe_update_interval_trans": 2.0, "keyframe_update_min_points": 500, "keyframe_update_strategy": "OVERLAP", "keyframe_voxel_resolution": 0.05, "keyframe_voxelmap_levels": 2, "keyframe_voxelmap_scaling_factor": 2.0, "max_keyframe_overlap": 0.6, "max_num_keyframes": 15, "registration_error_factor_type": "VGICP_GPU", "so_name": "libsub_mapping.so", "submap_downsample_resolution": 0.05, "submap_target_num_points": 100000, "submap_voxel_resolution": 0.05 } }

{ "global_mapping": { "between_registration_type": "GICP", "create_between_factors": true, "enable_imu": true, "enable_optimization": true, "init_pose_damping_scale": 10000000000.0, "isam2_relinearize_skip": 1, "isam2_relinearize_thresh": 0.1, "max_implicit_loop_distance": 100.0, "min_implicit_loop_overlap": 0.2, "randomsampling_rate": 1.0, "registration_error_factor_type": "VGICP_GPU", "so_name": "libglobal_mapping.so", "submap_voxel_resolution": 0.1, "submap_voxel_resolution_dmax": 20.0, "submap_voxel_resolution_dmin": 5.0, "submap_voxel_resolution_max": 1.0, "submap_voxelmap_levels": 2, "submap_voxelmap_scaling_factor": 2.0, "use_isam2_dogleg": false } }

it would be nice if someone could look up my parameters and make suggestions how to improve them. im pretty sure im still overlooking something.

Thanks in advance!

[koide3]

Please try the flat_earther plugin that enforces proximate submaps (or the entire map) to be on a flat floor. https://github.com/koide3/glim/issues/108 https://github.com/koide3/glim/issues/190