title: In ROS, how to transform pose from kinect frame to PR2's base_link frame?
body: <p>I am having confusion with tf. I am working on a grasping project. My vision partner is giving me a pose of an object in the camera frame or when running a robot, the robot's Kinect frame (PR2 robot). Now, in order to grasp that object, I need to get the pose in the robot's base_link frame as this frame is used by the moveit interface.</p>
  
  <p>Initially, my thinking was that I can do that using lookup transform method of tf but now I have come to know that this only gives transformation between different frames. In order to get what I need, which is the object's location in the base_link frame, I should use a transformListener method. I am still confused about the difference between the two. I am working with python. If anyone could give me a sample working transformListener code, that would be helpful as well.</p>