On: Where the Heat and the Thunder Hit Their Shots

[SoapSeller]

Not the NBA, but some teams use a system called SportVU[0] that do auto player&ball tracking.

I used to work on the system, so I can answer (some) questions about it.

[0] http://www.sportvu.com/basketball.asp

[hammock → SoapSeller]

How does it work?

[SoapSeller → hammock]

Short version: Using a number(six) of dedicated video cameras around the venue and (a lot of) image processing.

There is a nice article in wired about it(include a picture of one of the cameras and the view from another) http://www.wired.com/playbook/2011/04/nba-data-revolution/al...

[jevinskie → SoapSeller]

How is the system calibrated? Are the cameras at fixed angles or mounted to a base that measures their angles?

[SoapSeller → jevinskie]

The angles are important, but also the position relatively to the court(which is different in every venue).

The calibration is done by matching(automatically or manually) known world points to pixels from the cameras. (This is a very common practice in image-processing systems)

[statictype → SoapSeller]

Teams can install these cameras in their own arenas. Are they allowed to install it when their team plays in opposing arenas? Do they have to negotiate with various team owners for this?

[SoapSeller → statictype]

Unfortunately - they can't. There is a continues effort(by the company own the tech, and by the teams that are currently using it) to make it a standart in the league. At least in the previous season there was a sharing agreement between the teams that use the system(all the teams get all the data).