What lurks below Microsoft’s Surface? A brief Q&A with Microsoft

Minority Report meets the kitchen table in the new Surface from Microsoft. Claiming that surface computing is "as significant as the move from DOS to GUI," the company today announced a tabletop device with an integrated 30-inch screen and five cameras to enable multitouch access to music, photos, the web, and more. According to Microsoft, Surface isn't simply a regular PC with a touch interface—it's a whole new category of computing device that will supplement rather than replace traditional machines. We talked with Microsoft about the concept and what's powering it. 

Awash in the near-infrared

Surface features a touch interface, but it doesn't use a touch screen. Instead, five separate cameras are used to record motion on the table's surface. Ars spoke with Nigel Keam, a member of the Surface team, about the technology in the device, and he explained that five cameras were needed because of field angle issues. In order to get the table as low as it is, five cameras are used so that each one can have a small field of view. That translates into better resolution and speed (measured in pixels/second) than a single camera with an exceptionally wide-angle view of the table surface. 

The five cameras are near-infrared devices, but that's not because they are trying to read heat signatures from fingertips (or other body parts) on the table. Instead, it's because the entire surface of Surface is bathed in light; by illuminating the top of the table, the cameras can easily see when things are placed on it. Shining colored light across the surface of the table would spoil the effect that Microsoft wants, so near-infrared light is used for invisible illumination.

Those cameras, which are located below the acrylic surface of the table, can read a nearly infinite number of simultaneous touches, and are limited only by processing power. Keam says that Surface has been optimized for 52 touches—enough for four people to use all 10 fingers at once and still have 12 objects sitting on the table.

In addition to recognizing fingers, Surface can recognize inanimate objects. Microsoft has developed a 3/4" square tag called a "domino" that can be attached to objects so that Surface can interact with them on the fly. Instead of relying on RFID, the domino tag uses dots to encode its information (hence the name). There is a single dot in the center of the tag, three dots on one side for orientation, and space for eight more dots that are read as data. Essentially, it's a one-byte data tag.

When something like a tagged wineglass is set on the table, Surface illuminates the edges of the object with a soothing glow and can display information, pictures, or decorative graphics next to and around the glass. When the glass moves across the table, these items follow it. This is the sort of technology that sounds interesting but a bit ridiculous in press materials; however, the possibilities for such a device are staggering—especially when it drops in price and enters the home market. It's even possible that consumer electronics could be tagged at production, should the concept take off.

The hidden PC

Surface currently runs on a high-end PC but uses mainly conventional components. It's powered by a Core 2 Duo chip and a "newish video card," and the system runs on 2GB of RAM. Keam declined to give more specifics but said that all of the hardware was consumer tech. It uses a rear projection system for the display which projects the image to the underside of the tabletop. According to Keam, Surface runs on a standard Vista installation with a layer of code on top that is specific to the project; the underlying operating system has not been modified in any way. 

Surface applications can be written in Windows Presentation Foundation or XNA. The development process is much like normal Vista development, but custom WPF controls had to be created by the Surface team due to the unique interface of Surface. Developers already proficient in WPF have been trained in the idiosyncrasies of writing Surface apps and should be available to customize Surface deployments for the large hotels, casinos, and restaurants at which the machines will first be deployed.