============================
Monocular Camera Calibration
============================

.. note::

   These instructions are specifically for a monocular camera.
   To calibrate a stereoscopic camera, see `the camera_calibration
   instructions <http://wiki.ros.org/camera_calibration>`__.

1.  Set up your development environment by following the
    :doc:`Developer Environment Setup </getting_started/dev_env_setup>`.
2.  Print a large checkerboard with known dimensions.

    This tutorial uses a 6x8 checkerboard with 200mm squares.
    Calibration uses the interior vertex points of the checkerboard, so
    a “7x9” board uses the interior vertex parameter “6x8” as in the
    example below. Checkerboards with specific dimensions can be
    downloaded
    `here <https://calib.io/pages/camera-calibration-pattern-generator>`__.
3.  Clone the ROS 2 ``usb_cam`` package:

    .. code:: bash

        cd ${ISAAC_ROS_WS}/src && \
          git clone -b ros2 https://github.com/ros-drivers/usb_cam


    .. note::

        Your camera vendor might offer a specific ROS
        2-compatible camera driver package that can be used in place of
        the ``usb_cam`` package.

4.  Launch the Docker container using the ``run_dev.sh`` script:

    .. code:: bash

       cd ${ISAAC_ROS_WS}/src/isaac_ros_common && \
         ./scripts/run_dev.sh

5.  Inside the container, build, and source the workspace:

    .. code:: bash

       cd /workspaces/isaac_ros-dev && \
         colcon build --symlink-install && \
         source install/setup.bash

6.  Run the ``usb_cam`` image publisher:

    .. code:: bash

       ros2 run usb_cam usb_cam_node_exe --remap __ns:=/my_camera --ros-args -p framerate:=30.0 -p image_height:=720 -p image_width:=1280

7.  Attach another terminal to the Docker container using the
    ``run_dev.sh`` script:

    .. code:: bash

       cd ${ISAAC_ROS_WS}/src/isaac_ros_common && \
         ./scripts/run_dev.sh

8.  Run the camera calibrator:

    .. code:: bash

       ros2 run camera_calibration cameracalibrator --size 6x8 --square 0.20 image:=/my_camera/image_raw camera:=/my_camera

9.  Complete steps 6-8 from `this camera calibration
    tutorial <https://navigation.ros.org/tutorials/docs/camera_calibration.html>`__.
10. Make sure you press **Calibrate** and then the **Save** button.

    You should see the following line in the second terminal:

    .. code:: bash

       ('Wrote calibration data to', '/tmp/calibrationdata.tar.gz')

    The calibration file will be stored at
    ``/tmp/calibrationdata.tar.gz``.
11. After the calibration file has been saved, enter ``Ctrl+C`` in each
    terminal to stop the nodes.
12. Move the calibration file to the required location:

    .. code:: bash

         cd /workspaces/isaac_ros-dev/src/<isaac_ros_metapackage>/<isaac_ros_package>/config/ && \
         tar -xvf /tmp/calibrationdata.tar.gz -C ./ ost.yaml && \
         mv ost.yaml camera_info.yaml