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Overview

This package allows to localize handles in 3D point clouds. The video below demonstrates the method in a scenario where a robot has to pick up objects from a table and deposit them into a box.

Requirements

  1. ROS Hydro

  2. Lapack (install in Ubuntu using: sudo apt-get install liblapack-dev)
  3. Openni_launch (install in Ubuntu using: sudo apt-get install ros-hydro-openni-launch)

Installation

Ubuntu

  1. sudo apt-get install ros-hydro-handle-detector
  2. source /opt/ros/hydro/setup.bash

From Source

  1. Clone the github repository.
  2. Copy the cloned repository into the 'src' folder of your ROS workspace.
  3. Recompile your ROS workspace: $ catkin_make.

How to Localize handles

There are two ways in which handles can be localized using this package: from a *.pcd file that contains the point cloud data, or from the point cloud data provided by a depth sensor such as an RGB-D camera, e.g., Microsoft Kinect.

Using a point cloud file

  1. Set the parameter 'file' in handle_detector/launch/localization_pcd_file.launch to the absolute path of some pcd file.
  2. Start roscore: $ roscore.
  3. Run the handle localization: $ roslaunch handle_detector localization_pcd_file.launch.
  4. Use RViz to visualize the results (see below): $ rosrun rviz rviz.

Using a depth sensor

Note: This requires an openni-compatible device, and has only been tested with an Asus Xtion Pro.

  1. Set-up one or more objects in front of the RGB-D camera, and have the RGB-D camera running.
  2. Start roscore: $ roscore.
  3. Start openni_launch: $ roslaunch openni_launch openni.launch.
  4. Run the handle localization: $ roslaunch handle_detector localization_sensor.launch.
  5. Use RViz to visualize the results (see below): $ rosrun rviz rviz.

Grasp handles using localization information

  1. Follow the steps described in (C).
  2. Subscribe to the ROS topic /localization/handle_list to get a list of handles.
  3. This list gives the pose, radius, extent, major axis, and normal axis for each affordance (cylindrical shell) in every handle.
  4. To see the structure of the messages published here, use: $ rosmsg show handle_detector/nameOfMessage.
  5. Use the given localization information to decide for a target handle, and grasp it using your robot.

Visualization in RViz

  1. Show input point cloud: add a PointCloud2 and set the topic to /localization/point_cloud.

  2. Show all affordances: add a MarkerArray and set the topic to /localization/visualization_all_affordances.

  3. Show all handles: add a MarkerArray and set the topic to /localization/visualization_all_handles.

  4. Show handle i (i = 0, 1, ...): add a MarkerArray and set the topic to /localization/visualization_handle_i.

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Commands

  • Run handle localization on a *.pcd file: $ roslaunch handle_detector localization_pcd_file.launch
  • Run handle localization on range sensor input: $ roslaunch handle_detector localization_sensor.launch

Published ROS Topics

  • /localization/cylinder_list: contains a list of cylinders (affordances) with pose, radius, extent, major axis, and normal axis.

  • /localization/handle_list: contains a list of handles where each handle consists of a list of cylinders (affordances).

ROS Launch Parameters

Affordance Localization

file
the location of the *.pcd file on the file system (absolute path)
target_radius
the radius of the target handle
target_radius_error
the error permitted on the target radius
affordance_gap
the size of the gap around the affordance
sample_size
the number of point neighborhoods to be sampled from the point cloud
use_clearance_filter
whether the clearance filter (enough gap around affordance) is used
use_occlusion_filter
whether the occlusion filter is used
curvature_estimator
the method that is used to estimate curvature (0: Taubin Quadric Fitting, 1: Principal Component Analysis, 2: Normals)
point_cloud_source
the source of the point cloud (0: *.pcd file, 1: range sensor)
update_interval
the interval in seconds at which the algorithm is repeated
workspace_limits (6 parameters)
the minimum and maximum values of the workspace in three dimensions
num_threads
the number of CPU threads to use in Taubin Quadric Fitting

Handle Localization

ransac_runs
the number of times RANSAC is run to detect handles
ransac_min_inliers
the minimum number of colinear affordances in a handle
ransac_dist_radius
the axis distance below which two affordances are considered to belong to the same handle
ransac_orient_radius
the orientation distance below which two affordances are considered to belong to the same handle
ransac_radius_radius
the radius distance below which two affordances are considered to belong to the same handle

Wiki: handle_detector (last edited 2014-04-22 02:37:30 by AndreasTenPas)