Making Things See

Tracking Without Calibration: Hand Tracking and Center of Mass

In this section we’re going to look at two approaches to tracking users that don’t require calibration: hand tracking and center of mass detection. These methods both go beyond simply accessing the user pixels. They use advanced functionality available from OpenNI to boil down the depth pixels into a simple position that will be useful in our application.

Hand Tracking

The first technique for tracking users without requiring calibration is hand tracking (Figure 4-24). This is the simplest use of OpenNI’s wildly powerful and complex gesture recognition system, called NITE. This system allows us to detect the presence of the user’s hand and to track its movement without needing the user ...