- First, make sure the Astra SDK is working correctly:
  - cd <your directory>/AstraSDK/bin
  - ./SimpleBodyViewer-SFML
  You should see body tracking with Skeleton displayed.  If not, see Astra website.

- When the tracker is running, you should see something like this logged: 
  "Floor mask: width: 640 height: 480 bottom center value:"

- When tracking a person, you should see something like this logged:
  Body Id: 41 Status: Tracking
  Body 41 CenterOfMass (-143.216354, 15.024889, 827.818970)
      Joint Tracking Enabled: True     Hand Pose Recognition Enabled: True
  Astra: 2D Tracking for ID 41 :   px: 0.2441 py: 0.1192
      x: -0.07321 y: 0.1683 z: 0
            Head:Body 41 Joint 0 status 2 @ world (-27.8, 315.9, 974.3) depth (303.7, 55.1)

- When tracking, the following are published:
  - rostopic list
    /body_tracker/marker
    /body_tracker/position
    /body_tracker/skeleton
  - Confirm each with rostopic echo

- If the camera is mounted on a robot, and included in the URDF, the /body_tracker/marker
  topic will show the position of the user (spine joints) as balls in RVIZ.
  - make sure to add the topic /body_tracker/marker to see the tracking balls.

- You can safely ignore this warning: 
  "Warning: USB events thread - failed to set priority. This might cause loss of data..."      
- When robot is moving (or if Astra camera is mounted on a Pan/Tilt that is tracking a target)
  the Astra SDK will often think some object is a person.  So, it is important in your code to track
  individuals by ID, and ignore other ID's that are picked up (they may be bogus).
  I find it useful to use the Gesture to indicate which person in a scene is the correct person to track.

- Code written by me is provided under BSD license
- This package uses sample code from the Astra SDK, provided by Orbbec.  See Orbbec Astra SDK for licensing.