Holograms

Another interesting effect associated with Kinect is the pseudo-hologram. A 3D image can be made to tilt and shift based on the various positions of a person standing in front of Kinect. When done right, the effect creates the illusion that the 3D image exists in a 3D space that extends into the display monitor. Because of the 3D vector graphics capabilities of WPF, what I’ve described is actually easy to implement using Kinect and WPF. Figure 8-4 shows a simple 3D cube that can be made to rotate and scale depending on an observer’s position. The illusion only works when there is only a single observer, however.

Figure 8-4. 3D cube

This effect actually goes back to a Wii Remote hack that Johnny Chung Lee demonstrated at his 2008 TED talk. This is the same Johnny Lee who worked on the Kinect team for a while and also inspired the AdaFruit contest to hack together a community driver for the Kinect sensor. In Lee’s implementation, an infrared sensor from the Wii remote was placed on a pair of glasses, to track a person wearing the glasses as he moved around the room. The display would then rotate a complex 3D image based on the movements of the pair of glasses to create the hologram effect.