Microsoft is trying to patent the holodeck. Well, sort of. Back in early 2011, the company filed a patent application for an "immersive display experience" that combines primary and peripheral images to give users a better sense of their environment. A patent has yet to be granted, but the application is now online for all to see.
The application explains the relationship between the primary image, the peripheral image, and a depth camera that tracks the position of the user. The peripheral image is derived from the primary one, with corrective distortion applied based on the user's perspective, the topography of the room, and even the color of the walls and upholstery. A projector is tasked with displaying the peripheral image, which will have a lower resolution than the primary one.
Rather than being the focus of the user's attention, the peripheral image is designed to provide environmental awareness. As I've discovered using triple-screen surround gaming configs, even limited peripheral vision can enhance the gaming experience greatly. The lower-resolution image shouldn't be an issue, since the player's attention will be focused on the primary display.
True holodecks are still relegated to the realm of science fiction, but the system described in the patent application should be possible with today's technology. Microsoft's Kinect motion controller already offers depth camera functionality, and small projectors seem to be popping up everywhere. Adjusting the peripheral image to compensate for the environment may be the most challenging aspect of the entire system. Thanks to Ars Technica for the tip.