get_T_cam_world

  def get_T_cam_world(self, from_frame='kinect2_ir_optical_frame', to_frame='world'):
        """ get transformation from camera frame to world frame"""

        time = 0
        trans = None
        qat = None
        while not rospy.is_shutdown():
            try:
                time = self.tl.getLatestCommonTime(from_frame, to_frame)
                (trans, qat) = self.tl.lookupTransform(from_frame, to_frame, time)
                break
            except (tf.Exception,tf.LookupException,tf.ConnectivityException, tf.ExtrapolationException):
                print 'try again'
                continue

        print qat
        return RigidTransform(translation=trans, rotation=qat, from_frame=from_frame, to_frame=to_frame)