How to obtain the R and T of the kinect camera?

edit

i can't find the /camera/rgb/camera_info. is it under additional topics?

It's published when you run the openni_camera node.

published where? sorry i am blur

I'm not sure what more to tell you. If you're not familiar with publishing, you probably want to go over the tutorials again.

Running 'rostopic list' will show you all available topics. I'd definitely recommend the tutorials to get more comfortable with the different ROS tools and concepts <http://www.ros.org/wiki/ROS/Tutorials>.

Wim thanks... when i type rostopic echo/camera/depth/camera_info,i get matrices D, K, R and P... what are they for?

You can find the message documentation if CameraInfo here <http://www.ros.org/doc/api/sensor_msgs/html/msg/CameraInfo.html>. In general, you can find a link to the message documentation from the package page. So the CameraInfo link is found here <http://www.ros.org/wiki/sensor_msgs>.