opencv_cam

A simple ROS2 camera driver based on OpenCV.

Supports ROS2 intra-process comms.

Requires ROS2 and ros-$ROS_DISTRO-camera-calibration-parsers. Builds for ROS2 Foxy, Galactic, Humble and Iron.

Install and build

mkdir ~/ros2/opencv_cam_ws/src
cd ~/ros2/opencv_cam_ws/src
git clone https://github.com/clydemcqueen/opencv_cam.git
git clone https://github.com/ptrmu/ros2_shared.git
cd ~/ros2/opencv_cam_ws/
source /opt/ros/$ROS_DISTRO/setup.bash
colcon build

Usage

Default is to publish images from /dev/video0:

ros2 run opencv_cam opencv_cam_main

A more complex example:

ros2 run opencv_cam opencv_cam_main --ros-args --remap /image_raw:=/my_camera/image_raw --params-file opencv_cam_params.yaml

... where opencv_cam_params.yaml is:

/opencv_cam:
  ros__parameters:
    file: True
    filename: 'my_camera.MOV'
    camera_info_path: 'my_camera_info.ini'
    camera_frame_id: 'my_camera'

Intra-process comms

IPC test -- CLI composition:

# First shell
ros2 run rclcpp_components component_container

# Second shell (ignore the deprecation warning, see https://github.com/ros2/ros2cli/issues/336)
ros2 component load /ComponentManager opencv_cam opencv_cam::ImageSubscriberNode -e use_intra_process_comms:=true
ros2 component load /ComponentManager opencv_cam opencv_cam::OpencvCamNode -e use_intra_process_comms:=true

Launch file composition:

ros2 launch opencv_cam composition_launch.py

Manual composition -- handy for debugging:

ros2 run opencv_cam ipc_test_main

Parameters

Parameter	Type	Default	Notes
file	bool	False	Read from file vs. read from device
fps	int	0	Framerate. Specify 0 to publish at the recorded (file) or default (device) framerate
filename	string	""	Filename, ignored if file is False
index	int	0	Device index, 0 for /dev/video0. Ignored if file is True
width	int	0	Device width in pixels. Specify 0 for default. Ignored if file is True
height	int	0	Device width in pixels. Specify 0 for default. Ignored if file is True
camera_info_path	string	"info.ini"	Camera info path
camera_frame	string	"camera_frame"	Camera frame id

Camera info file formats

Uses the ROS standard camera calibration formats. Files must end in .ini or .yaml.