How to access and use skeleton joint coordinates using OpenNI, ASUS Xtion, and ROS?

Question

To develop a person follower robot, I am using ASUS Xtion and OpenNI. To obtain both RGB image and skeleton joints, I am using a skeleton tracker script (https://github.com/Chaos84/skeleton_tracker). Tracker publishes joints in "/tf" But the thing is that I cannot use those joint coordinates in my script. I don't know how to access them. How can I access and use them in my script to make the robot move according to those coordinates? Thanks.

Answer 1

You can use another skeleton detection/tracker, the BodySkeletonTracker:

https://github.com/derzu/BodySkeletonTracker

Look how does it works:

You can get the joints points getting an object of the class SkeletonPoints.

Answer 2

To get joint coordinates and angles from a /tf topic, you need to right a tf listener which is explained in this link.

Also you can look at one of my ROS packages where I wrote tf listener using OpenNI and ASUS Xtion. Here is the link.