On the RoboRIO


Image processing is a CPU intensive task, and because of the Python Global Interpreter Lock (GIL) we do NOT recommend using robotpy-cscore directly in your robot process. Don’t do it. Really.

Instead, we provide easy to use ways to launch your camera/image processing code from your Python robot code, and it won’t break simulation either! See below for details.

For more information on the GIL and its effects, you may wish to read the following resources:


The following assumes you’re writing your robot code and your image processing code using RobotPy. However, if you’re writing your Robot code using Java, we do have an example which would allow you to launch Python image processing code from your Java Robot code. See this file for details.


robotpy-cscore can be easily installed with the RobotPy installer. See these instructions for details.

Automatic camera streaming

If you do not wish to modify or process the images from your camera, and only wish to stream a single camera via HTTP to a dashboard, then you only need to add the following to your robotInit function:


That’s it! You should be able to connect to the camera using SmartDashboard, the default LabVIEW Dashboard, or if you point your browser at http://roborio-XXXX-frc.local:1181.

The quick vision example can be found in the RobotPy examples repository.

Image processing

Because the GIL exists (see above), RobotPy’s WPILib implementation provides a way to run your image processing code in a separate process. This introduces a number of rules that your image processing code must follow to efficiently and safely run on the RoboRIO:

  • Your image processing code must be in its own file

  • Never import the cscore package from your robot code, it will just waste memory

  • Never import the wpilib or hal packages from your image processing code


    wpilib may not be imported from two programs on the RoboRIO. If this happens, the second program will attempt to kill the first program.

vision file

The first step you need to do is create a file – let’s call it vision.py, and stick it in the same directory as your robot.py file. You can also put it in a subdirectory underneath your robot code, and the robot deploy command will copy it to the robot.


Once you have written your cscore code, in the robotInit function in your robot.py file you need to add the following line:


The parameter provided to launch is of the form FILENAME:FUNCTION. For example, if your code was located in the camera subdirectory in a file called targeting.py, and your function was called run, then you would do:


Important notes

  • Your image processing code will be launched via a stub that will setup logging and initialize pynetworktables to talk to your robot code
  • The child process will NOT be launched when running the robot code in simulation or unit testing mode
  • If your image processing code contains a if __name__ == '__main__': block, the code inside that block will NOT be executed when the code is launched from robot.py
  • The camera code will be killed when the robot.py program exits. If you wish to perform cleanup, you should register an atexit handler.

The intermediate vision example can be found in the RobotPy examples repository.

More information