Can anybody please tell how to use web camera in ROS? [closed]

edit

I want to use webcamera to test images in ROS. I am programming using OPENCV and want to see the live video stream from my laptop in a window on ROS. When I try to launch a file whose contents are given below, I get an error that "ERROR: cannot launch node of type [uvc_cam/uvc_cam_node]: can't locate node [uvc_cam_node] in package [uvc_cam] No processes to monitor :". I launch the file using the command : roslaunch ishan_vision uvc_cam.launch device:=/dev/video0

uvc_cam.launch file :

<launch> <arg name="device" default="/dev/video0"/>

<node name="uvc_cam_node" pkg="uvc_cam" type="uvc_cam_node" output="screen">
    <remap from="camera/image_raw" to="camera/rgb/image_color" />
    <param name="device" value="$(arg device)" />
    <param name="width" value="320" />
    <param name="height" value="240" />
    <param name="frame_rate" value="20" />
    <param name="exposure" value="0" />
    <param name="gain" value="100" /> 
</node>

</launch>

Can anybody please help?

Thanks