ROS 教程之 vision : 用各种摄像头获取图像

参考：http://blog.csdn.net/heyijia0327/article/details/41623419

用外部USB摄像头采集图像

安装usb_cam package：

cd ~/catkin_ws/src  git clone https://github.com/bosch-ros-pkg/usb_cam.git  cd ~/catkin_ws  catkin_make

source /home/xcmai/catkin_ws/devel/setup.bash

或

export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:/home/xcmai/catkin_ws

在/home/xcmai/catkin_ws/src/usb_cam/launch下，usb_cam-test.launch里面增加参数，也可以不修改。修改后如下：

<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="640" />    <param name="image_height" value="480" />    <param name="framerate" value="30" />     <param name="pixel_format" value="yuyv" />    <param name="camera_frame_id" value="usb_cam" />    <param name="io_method" value="mmap"/>    <param name="brightness" value="128" />      <param name="contrast" value="128" />      <param name="saturation " value="70" />   </node>  <node name="image_view" pkg="image_view" type="image_view" respawn="false" output="screen">    <remap from="image" to="/usb_cam/image_raw"/>    <param name="autosize" value="true" />  </node>  <remap from="usb_cam_node/image_raw" to="camera/rgb/image_color" />          <param name="video_device" value="$(arg device)" />   </launch>

Note: 当不是用usb_cam这个package时，倒数第六行的内容可以是
remap from=”image” to=”/camera/image_raw”/

把webcam插入台式机，/dev下出现video0。

启动：
先启动roscore，再在另一个窗口roslaunch，

roslaunch usb_cam usb_cam-test.launch device:=/dev/video0

Note: 在这里roslaunch的语法：

roslaunch package_name launch_file_name device:=/dev/video0

下面就是在ROS下操作opencv写算法了，照着《ROS by example 1》中第10章学习就行了。