Using ROS for Linux

Using ROS for Linux

Robot Operating System (ROS) provides libraries and tools to help software developers create robot applications. It provides hardware abstraction, device drivers, libraries, visualizers, message-passing, package management, and more. This document shows how to install arena_camera, LUCID’s ROS driver.

System Requirements

Initial ROS Setup

  1. Set up your system to acquire software from packages.ros.org.

    $ sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) \main" > /etc/apt/sources.list.d/ros-latest.list'

    You can confirm the new list file is set by checking the contents of ros-latest.list:

    On Ubunto 16.04 (xenial):
    ROS and Ubuntu v16 Lucid Camera

    On Ubuntu 18.04 (bionic):
    ROS and Ubuntu v18 Lucid Camera

  2. Use apt-key to install the Open Robotics key to your list of trusted keys.

    $ sudo apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654

  3. Install ROS Desktop. The following commands will install ROS onto the system.

    On Ubuntu 16.04 (xenial):

    $ sudo apt-get update$ sudo apt-get install ros-kinetic-desktop-full

    On Ubuntu 18.04 (bionic):

    $ sudo apt-get update$ sudo apt-get install ros-melodic-desktop-full

  4. Initialize rosdep. This will setup system dependencies for ROS.

    $ sudo apt-get install python-rosdep$ sudo rosdep init$ rosdep update

  5. Setup ROS environment variables.

    On Ubuntu 16.04 (xenial):

    $ echo "source /opt/ros/kinetic/setup.bash" >> ~/.bashrc$ source ~/.bashrc

    On Ubuntu 18.04 (bionic):

    $ echo "source /opt/ros/melodic/setup.bash" >> ~/.bashrc$ source ~/.bashrc

  6. Install ROS package workspace dependencies. This will allow you to create and manage your own ROS workspaces, including the ROS workspace used by arena_camera.

    $ sudo apt-get install python-rosinstall python-rosinstall-generator python-wstool build-essential

Arena SDK Setup

  1. Download and install Arena SDK. Arena SDK for Linux is available on the Downloads page at https://thinklucid.com/downloads-hub/. The Arena SDK dependencies are listed in the README file included with the SDK.

Note: These instructions will assume Arena SDK is installed at ~/ArenaSDK_Linux_x64:

$ tar -xvf ArenaSDK_v0.1.26_Linux_x64.tar.gz -C ~

Please remember to go over the Getting Started steps discussed in the Arena SDK documentation and run the Arena_SDK.conf file in the Arena_SDK directory:

$ cd ~/ArenaSDK_Linux_x64/
$ sudo sh Arena_SDK.conf

  1. Set up your ARENA_ROOT environment variable. This environment variable should be the path where you have installed Arena SDK.

$ echo "export ARENA_ROOT=~/ArenaSDK_Linux_x64" >> ~/.bashrc$ source ~/.bashrc

You can confirm the variable is set with the typing echo $ARENA_ROOT in the terminal.

arena_root_ros

Creating a ROS workspace for the arena_camera ROS Driver

  1. Set up your system to acquire software from packages.ros.org.

Note: These instructions will assume catkin_ws is located at ~/catkin_ws:

$ unzip arena_camera_ros-1.2.zip -d ~
$ mv ~/arena_camera_ros-1.2/catkin_ws ~

  1. Set up your ARENA_CONFIG_ROOT environment variable. This is also the path to the ROS workspace used by arena_camera.

    $ echo "export ARENA_CONFIG_ROOT=~/catkin_ws" >> ~/.bashrc$ source ~/.bashrc

Building and Running the arena_camera ROS Driver

    1. Navigate to your arena_camera ROS workspace

$ cd ~/catkin_ws

  1. Copy the included image_encoding.h to your ROS include folder

    On Ubuntu 16.04 (xenial):

    $ sudo cp /opt/ros/kinetic/include/sensor_msgs/image_encodings.h /opt/ros/kinetic/include/sensor_msgs/image_encodings.h.bak$ sudo cp inc/image_encodings.h /opt/ros/kinetic/include/sensor_msgs/image_encodings.h

    On Ubuntu 18.04 (bionic):

    $ sudo cp /opt/ros/melodic/include/sensor_msgs/image_encodings.h /opt/ros/melodic/include/sensor_msgs/image_encodings.h.bak$ sudo cp inc/image_encodings.h /opt/ros/melodic/include/sensor_msgs/image_encodings.h

Note: A custom image_encoding.h is included to enable streaming support for LUCID’s Helios camera.

  1. Build arena_camera

    $ catkin_make

    The above command will build:

    • arena_camera: The Arena SDK camera code for ROS.
    • arena_camera_node: The ROS node for arena_camera. See
    http://wiki.ros.org/ROS/Tutorials/UnderstandingNodes
    for further information.

    build-arena-camera-ROS

  2. Run roscore to start the ROS server

    $ roscore

    roscore

Note: Only one roscore can be run at a time.

  1. Run arena_camera as a node in a new terminal. The first command listed below will overlay your workspace on top of your ROS environment. The second command will connect to the camera and the camera will start imaging. The received images will be published to a topic. See http://wiki.ros.org/Topics and http://wiki.ros.org/ROS/Tutorials/UnderstandingTopics for further information.

    $ source ~/catkin_ws/devel/setup.bash$ rosrun arena_camera arena_camera_node

    arena_camera ROS

  2. View the raw images by opening a new terminal and subscribing the image_view node to topic name image_raw.

    $ rosrun image_view image_view image:=/arena_camera_node/image_raw

    Image-RAW-ROS

Note: Streaming with 12-bit pixel formats are not supported in this version of arena_camera. Depth visualization support is not included with this version of arena_camera. You will see a black image when viewing a Coord3D pixel format with the image_view node.

Using rosparam to Set Camera Parameters

  1. ROS includes the rosparam tool which can be used to set camera parameters before starting arena_camera.

    To set a parameter:

    $ rosparam set /arena_camera_node/<parameter_name> value$ rosparam set /arena_camera_node/frame_rate 10$ rosparam set /arena_camera_node/image_encoding mono8

    To list of parameters that are already set:

    $ rosparam list /arena_camera_node

    To view a set parameter’s value:

    $ rosparam get /arena_camera_node/<parameter_name>$ rosparam get /arena_camera_node/frame_rate

    To delete a set parameter:

    $ rosparam delete /arena_camera_node/<parameter_name>$ rosparam delete /arena_camera_node/frame_rate

Other rosparam commands

Command Description
rosparam dump Dump current parameters to a file
rosparam load Load parameters from a file

Note: If arena_camera is already running, you must stop and start arena_camera for new or changed parameters to take effect.

Supported arena_camera_node Parameters

Parameter Description
device_user_id Device User ID (user defined name)
frame_rate Frame Rate (Hz)
image_encoding Pixel Format
binning_x Binning parameter for X axis (must match binning_y)
binning_y Binning parameter for Y axis (must match binning_x)
exposure Exposure Time (microseconds)
gain Gain (dB)
gamma Gamma correction of pixel intensity/td>
exposure_auto Auto Exposure control (true/false)
gain_auto Auto Gain control (true/false)

ROS camera_calibration Node

An optional step is to calibrate a single camera using the ROS camera_calibration node. This will assist in calibrating a monocular camera from the image_raw topic. See http://wiki.ros.org/camera_calibration/Tutorials/MonocularCalibration for more detailed information.

Once you have installed camera_calibration with rosdep, you can use it with arena_camera:

$ rosrun camera_calibration cameracalibrator.py   --no-service-check --size 8x6 --square 0.108 image:=/arena_camera_node/image_raw camera:=/camera

where 8×6 is the number of vertices in your checkerboard pattern.

camera calibration for ROS

Once there is enough data for calibration, click Calibrate to start the calibration process and click Save to save the calibration data to a file.

Note: You will not be able to Commit the calibration data onto the camera.

Once the calibration data is saved to file, you can extract the calibration tarball contents and apply the calibration to the camera using rosparam. The following steps assume the calibration data is extracted to ~/calibration.

$ mkdir ~/calibration $ tar -xvf /tmp/calibrationdata.tar.gz -C ~/calibration$ rosparam set /arena_camera_node/camera_info_url "file://home/ubuntu/calibration/ost.yaml"$ rosrun arena_camera arena_camera_node

rosparam