 Please ask about problems and questions regarding this tutorial on answers.ros.org. Don't forget to include in your question the link to this page, the versions of your OS & ROS, and also add appropriate tags. |
ConvexHull planar surface reconstruction
Description: ConvexHull planar surface reconstructionTutorial Level: BEGINNER
Contents
The following launch file starts a nodelet manager together with a VoxelGrid PCL filter nodelet. The input PointCloud2 topic is set to /camera/depth/points.
The default filtering values are set to filter data on the z-axis between 0.01 and 1.5 meters, and downsample the data with a leaf size of 0.01 meters.
The segmentation is performed by first estimating surface normals at each point for a support of 0.015 meters, and then using a RANSAC-based estimator for fitting planes with a threshold of 0.1 meters, and a normal deviation of ~5 degrees (0.09 radians).
The convex hull of the projected planar inliers is estimated and published on the /convex_hull/output topic.
1 <launch>
2 <node pkg="nodelet" type="nodelet" name="pcl_manager" args="manager" output="screen" />
3
4 <!-- Run a VoxelGrid filter to clean NaNs and downsample the data -->
5 <node pkg="nodelet" type="nodelet" name="voxel_grid" args="load pcl/VoxelGrid pcl_manager" output="screen">
6 <remap from="~input" to="/camera/depth/points" />
7 <rosparam>
8 filter_field_name: z
9 filter_limit_min: 0.01
10 filter_limit_max: 1.5
11 filter_limit_negative: False
12 leaf_size: 0.01
13 </rosparam>
14 </node>
15
16 <!-- Estimate point normals -->
17 <node pkg="nodelet" type="nodelet" name="normal_estimation" args="load pcl/NormalEstimation pcl_manager" output="screen">
18 <remap from="~input" to="/voxel_grid/output" />
19 <rosparam>
20 # -[ Mandatory parameters
21 k_search: 0
22 radius_search: 0.015
23 # Set the spatial locator. Possible values are: 0 (ANN), 1 (FLANN), 2 (organized)
24 spatial_locator: 0
25 </rosparam>
26 </node>
27
28 <!-- Segment the table plane -->
29 <node pkg="nodelet" type="nodelet" name="planar_segmentation" args="load pcl/SACSegmentationFromNormals pcl_manager" output="screen">
30 <remap from="~input" to="/voxel_grid/output" />
31 <remap from="~normals" to="/normal_estimation/output" />
32 <rosparam>
33 # -[ Mandatory parameters
34
35 # model_type:
36 # 0: SACMODEL_PLANE
37 # 1: SACMODEL_LINE
38 # 2: SACMODEL_CIRCLE2D
39 # 3: SACMODEL_CIRCLE3D
40 # 4: SACMODEL_SPHERE
41 # 5: SACMODEL_CYLINDER
42 # 6: SACMODEL_CONE
43 # 7: SACMODEL_TORUS
44 # 8: SACMODEL_PARALLEL_LINE
45 # 9: SACMODEL_PERPENDICULAR_PLANE
46 # 10: SACMODEL_PARALLEL_LINES
47 # 11: SACMODEL_NORMAL_PLANE
48 # 12: SACMODEL_NORMAL_SPHERE
49 # 13: SACMODEL_REGISTRATION
50 # 14: SACMODEL_REGISTRATION_2D
51 # 15: SACMODEL_PARALLEL_PLANE
52 # 16: SACMODEL_NORMAL_PARALLEL_PLANE
53 # 17: SACMODEL_STICK
54 model_type: 11
55 distance_threshold: 0.01
56 max_iterations: 1000
57 method_type: 0
58 optimize_coefficients: true
59 normal_distance_weight: 0.1
60 eps_angle: 0.09
61 </rosparam>
62 </node>
63
64 <node pkg="nodelet" type="nodelet" name="extract_plane_indices" args="load pcl/ExtractIndices pcl_manager" output="screen">
65 <remap from="~input" to="/voxel_grid/output" />
66 <remap from="~indices" to="/planar_segmentation/inliers" />
67 <rosparam>
68 negative: true
69 </rosparam>
70 </node>
71
72 <!-- Project the planar inliers -->
73 <node pkg="nodelet" type="nodelet" name="project_plane_inliers" args="load pcl/ProjectInliers pcl_manager" output="screen">
74 <remap from="~input" to="/voxel_grid/output" />
75 <remap from="~indices" to="/planar_segmentation/inliers" />
76 <remap from="~model" to="/planar_segmentation/model" />
77 <rosparam>
78 model_type: 11
79 copy_all_data: false
80 copy_all_fields: true
81 </rosparam>
82 </node>
83
84 <!-- Compute the convex hull -->
85 <node pkg="nodelet" type="nodelet" name="convex_hull" args="load pcl/ConvexHull2D pcl_manager" output="screen">
86 <remap from="~input" to="/project_plane_inliers/output" />
87 </node>
88 </launch>
