ROS Camera Topic

What is a ros topic? http://wiki.ros.org/Topics
ROS can publish the webcam stream to a “topic”, and any part of the robot can subscribe to it, by name, if it is interested in that data. ROS is almost like a program where everything is a global variable.

https://answers.ros.org/question/218228/ros-example-program-doesnt-work-with-the-laptop-webcam/

I made this file for the laptop webcam, but then didn’t end up using it.

<launch>
  <group ns="camera">
    <node pkg="libuvc_camera" type="camera_node" name="mycam">
      <!-- Parameters used to find the camera -->
      <param name="vendor" value="0x2232"/>
      <param name="product" value="0x1082"/>
      <param name="serial" value=""/>
      <!-- If the above parameters aren't unique, choose the first match: -->
      <param name="index" value="0"/>

      <!-- Image size and type -->
      <param name="width" value="640"/>
      <param name="height" value="480"/>
      <!-- choose whichever uncompressed format the camera supports: -->
      <param name="video_mode" value="uncompressed"/> <!-- or yuyv/nv12/mjpeg -->
      <param name="frame_rate" value="15"/>

      <param name="timestamp_method" value="start"/> <!-- start of frame -->
      <param name="camera_info_url" value="file:///tmp/cam.yaml"/>

      <param name="auto_exposure" value="3"/> <!-- use aperture_priority auto exposure -->
      <param name="auto_white_balance" value="false"/>
    </node>
  </group>
</launch>

roscore

apt install ros-melodic-uvc-camera

rospack listnames

rosrun uvc_camera uvc_camera_node _device:=/dev/video0

rostopic list

(should show /image_raw now…)

rosrun dso_ros dso_live calib=/opt/catkin_ws/src/dso_ros/camera.txt image:=/image_raw/