This is definitely one of the coolest applications for computer vision. The flying robot is receiving control information from a computer vision system that watches the court and tracks the tennis ball. Stick with the video long enough to see two of these robots keeping a volley going between each other. http://www.extremetech.com/article2/0,2845,2383177,00.asp
![flying robot tennis](https://www.edge-ai-vision.com/wp-content/uploads/2011/04/flying-robot-tennis-1024x610.jpg)