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elevation_map_loader#

Purpose#

This package provides elevation map for compare_map_segmentation.

Inner-workings / Algorithms#

Generate elevation_map from subscribed pointcloud_map and vector_map and publish it. Save the generated elevation_map locally and load it from next time.

The elevation value of each cell is the average value of z of the points of the lowest cluster.
Cells with No elevation value can be inpainted using the values of neighboring cells.

Inputs / Outputs#

Input#

Name Type Description
input/pointcloud_map sensor_msgs::msg::PointCloud2 The point cloud map
input/vector_map autoware_auto_mapping_msgs::msg::HADMapBin (Optional) The binary data of lanelet2 map

Output#

Name Type Description
output/elevation_map grid_map_msgs::msg::GridMap The elevation map
output/elevation_map_cloud sensor_msgs::msg::PointCloud2 (Optional) The point cloud generated from the value of elevation map

Parameters#

Node parameters#

Name Type Description Default value
map_layer_name std::string elevation_map layer name elevation
param_file_path std::string GridMap parameters config path_default
elevation_map_file_path std::string elevation_map file (bag2) path_default
map_frame std::string map_frame when loading elevation_map file map
use_inpaint bool Whether to inpaint empty cells true
inpaint_radius float Radius of a circular neighborhood of each point inpainted that is considered by the algorithm [m] 0.3
use_elevation_map_cloud_publisher bool Whether to publish output/elevation_map_cloud false
use_lane_filter bool Whether to filter elevation_map with vector_map false
lane_margin float Value of how much to expand the range of vector_map [m] 0.5
lane_height_diff_thresh float Only point clouds in the height range of this value from vector_map are used to generate elevation_map [m] 1.0
lane_filter_voxel_size_x float Voxel size x for calculating point clouds in vector_map [m] 0.04
lane_filter_voxel_size_y float Voxel size y for calculating point clouds in vector_map [m] 0.04
lane_filter_voxel_size_z float Voxel size z for calculating point clouds in vector_map [m] 0.04

GridMap parameters#

The parameters are described on config/elevation_map_parameters.yaml.

General parameters#

Name Type Description Default value
pcl_grid_map_extraction/num_processing_threads int Number of threads for processing grid map cells. Filtering of the raw input point cloud is not parallelized. 12

Grid map parameters#

See: https://github.com/ANYbotics/grid_map/tree/ros2/grid_map_pcl

Resulting grid map parameters.

Name Type Description Default value
pcl_grid_map_extraction/grid_map/min_num_points_per_cell int Minimum number of points in the point cloud that have to fall within any of the grid map cells. Otherwise the cell elevation will be set to NaN. 3
pcl_grid_map_extraction/grid_map/resolution float Resolution of the grid map. Width and length are computed automatically. 0.3
pcl_grid_map_extraction/grid_map/height_type int The parameter that determine the elevation of a cell 0: Smallest value among the average values of each cluster, 1: Mean value of the cluster with the most points 1
pcl_grid_map_extraction/grid_map/height_thresh float Height range from the smallest cluster (Only for height_type 1) 1.0

Point Cloud Pre-processing Parameters#

Rigid body transform parameters#

Rigid body transform that is applied to the point cloud before computing elevation.

Name Type Description Default value
pcl_grid_map_extraction/cloud_transform/translation float Translation (xyz) that is applied to the input point cloud before computing elevation. 0.0
pcl_grid_map_extraction/cloud_transform/rotation float Rotation (intrinsic rotation, convention X-Y'-Z'') that is applied to the input point cloud before computing elevation. 0.0

Cluster extraction parameters#

Cluster extraction is based on pcl algorithms. See https://pointclouds.org/documentation/tutorials/cluster_extraction.html for more details.

Name Type Description Default value
pcl_grid_map_extraction/cluster_extraction/cluster_tolerance float Distance between points below which they will still be considered part of one cluster. 0.2
pcl_grid_map_extraction/cluster_extraction/min_num_points int Min number of points that a cluster needs to have (otherwise it will be discarded). 3
pcl_grid_map_extraction/cluster_extraction/max_num_points int Max number of points that a cluster can have (otherwise it will be discarded). 1000000

Outlier removal parameters#

See https://pointclouds.org/documentation/tutorials/statistical_outlier.html for more explanation on outlier removal.

Name Type Description Default value
pcl_grid_map_extraction/outlier_removal/is_remove_outliers float Whether to perform statistical outlier removal. false
pcl_grid_map_extraction/outlier_removal/mean_K float Number of neighbours to analyze for estimating statistics of a point. 10
pcl_grid_map_extraction/outlier_removal/stddev_threshold float Number of standard deviations under which points are considered to be inliers. 1.0

Subsampling parameters#

See https://pointclouds.org/documentation/tutorials/voxel_grid.html for more explanation on point cloud downsampling.

Name Type Description Default value
pcl_grid_map_extraction/downsampling/is_downsample_cloud bool Whether to perform downsampling or not. false
pcl_grid_map_extraction/downsampling/voxel_size float Voxel sizes (xyz) in meters. 0.02
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