Update README: use camera_frame_id as fixed frame

readme.md

@@ -96,7 +96,7 @@ This is the official DOPE ROS package for detection and 6-DoF pose estimation of
 
 * To debug in RViz, `rosrun rviz rviz`, then either
   * `Add > Image` to view the raw RGB image or the image with cuboids overlaid
-  * `Add > Pose` to view the object coordinate frame in 3D.  If you do not have a coordinate frame set up, you can run this static transformation: `rosrun tf2_ros static_transform_publisher 0 0 0 0.7071 0 0 -0.7071 world <camera_frame_id>`, where `<camera_frame_id>` is the `frame_id` of your input camera messages.  Make sure that in RViz's `Global Options`, the `Fixed Frame` is set to `world`.
+  * `Add > Pose` to view the object coordinate frame in 3D.  If you do not have a coordinate frame set up, you can run this static transformation: `rosrun tf2_ros static_transform_publisher 0 0 0 0.7071 0 0 -0.7071 world <camera_frame_id>`, where `<camera_frame_id>` is the `frame_id` of your input camera messages.  Make sure that in RViz's `Global Options`, the `Fixed Frame` is set to `world`. Alternatively, you can skip the `static_transform_publisher` step and directly set the `Fixed Frame` to your `<camera_frame_id>`.
 
 * If `rosrun` does not find the package (`[rospack] Error: package 'dope' not found`), be sure that you called `source devel/setup.bash` as mentioned above.  To find the package, run `rospack find dope`.