How to use a USB camera with ROS on the Raspberry Pi or BeagleBone Blue - for streaming video to a large computer

This tutorial is about how to connect a USB camera to the Raspberry Pi or BeagleBone Blue and use it with ROS (Robot Operating System) - to read data from the camera via ROS image_view and even stream the video to a web browser!

At the end of the video demonstration on the robot EduMip.

1) As a bonus, we will create a distributed ROS system.

2) The Roscore application and the image viewer will work on the PC (master) and the camera node on the Raspberry Pi (slave).

3) To set up master and slave, we need to update the environment variables on both devices.

4) On the wizard: find the IP address of the device. For ethernet, net_dev can be either enpXXs0 or ethX:

$ ifconfig {net_dev} ifconfig enp61s0   ifconfig 

5) Use the IP address as the value for the ROS_IP variable:

 $ export ROS_IP="10.42.0.1" 

6) And for ROS_MASTER_URI:

 $ export ROS_MASTER_URI="http://10.42.0.1:11311" 

7) If you want to use these values ​​for future sessions, you can save the values ​​in a .bashrc file in your home directory:

 $ echo 'export ROS_IP="10.42.0.1"' >> ~/.bashrc $ echo 'export ROS_MASTER_URI="http://10.42.0.1:11311"' >> ~/.bashrc 

8) Connect to the Raspberry Pi via ssh:

 $ ssh {user}@{raspberry_ip} 

9) For RPi as a slave device, add the main IP address for ROS_MASTER_URI

10) And the IP address of the Raspberry Pi for ROS_IP

 $ export ROS_IP="10.42.0.65" $ export ROS_MASTER_URI="http://10.42.0.1:11311"  $ echo 'export ROS_IP="10.42.0.65"' >> ~/.bashrc $ echo 'export ROS_MASTER_URI="http://10.42.0.1:11311"' >> ~/.bashrc 

11) Now it's time to connect a USB camera.

12) Check if the camera is recognized by the system ::

 $ lsusb $ ls /dev | grep video* 

13) Install the node ROS usb_cam with the necessary dependencies:

 $ sudo apt install ros-kinetic-usb-cam 

14) The usb_cam node already has a test startup file:

 $ cat /opt/ros/kinetic/share/usb_cam/launch/usb_cam-test.launch 

15) Before launching this file, let's run the ROS kernel on master:

 $ roscore 

16) And now run the usb_cam node on the slave:

 $ roslaunch usb_cam usb_cam-test.launch 

17) Now we can see the topics created. We can check them either on the master or on the slave.

18) Put the current process in the background using CTRL + Z and execute the bg command to continue execution in the background. (on Ubuntu version not full desktop and no screen, just run another terminal)

19) To see the themes in the terminal:

 $ rostopic list 

20) ... or in the graphical interface:

 $ rqt_graph 

21) Reading camera data using image_view:

 $ rosrun image_view image_view image:=/usb_cam/image_raw 

22) Or using rqt_image_view

23) Move the background task to the fore:

 $ fg 

24) The latest experiment to date - streaming to the web

25) Installing a ROS web video server:

 $ sudo apt install ros-kinetic-web-video-server 

26) To do this correctly, create a catkin workspace for our custom startup file:

 $ mkdir -p ~/rosvid_ws/src $ cd ~/rosvid_ws $ catkin_make $ source devel/setup.bash 

27) Then create the ROS package:

 $ cd src $ catkin_create_pkg vidsrv std_msgs rospy roscpp 

28) Create a startup file using nano, vim, etc .:

 $ mkdir -p vidsrv/launch $ nano vidsrv/launch/vidsrv.launch 

place the code there from here

On Beaglebone Blue with an A4Tech usb camera, I had this code:

 <launch> <!-- This node description you can take from usb_cam-test.launch --> <node name="usb_cam" pkg="usb_cam" type="usb_cam_node" output="screen" > <param name="video_device" value="/dev/video0" /> <param name="image_width" value="352" /> <param name="image_height" value="288" /> <param name="pixel_format" value="mjpeg" /> <param name="camera_frame_id" value="usb_cam" /> <param name="io_method" value="mmap"/> </node> <!-- This node will launch web video server --> <node name="web_video_server" pkg="web_video_server" type="web_video_server" \ /> </launch> 

29) Assemble the package:

 $ cd .. $ catkin_make 

30) Run the ROS kernel on master again:

 $ roscore 

31) And run the generated startup file:

 $ roslaunch vidsrv vidsrv.launch 

32) The default web video server port is 8080

33) Open URL in web browser: {RPi_IP}: 8080

Links to documentation:

→ Video server node
→ USB camera node
→ rqt image viewer
→ Raspberry Pi Camera Module node

You can use almost any USB camera that has drivers for linux; you can also use the Raspberry Pi Camera Module link above in the same way.

An example of how this works on BeagleBone Blue with an A4Tech camera:



Search for a three card for video from a USB camera BealeBone Blue (the recognition algorithm works on a laptop with master ROS).