BIDI Display: Touch-Screen and Off-Screen

Recently, a prototype of an LCD screen has been developed which is able to “see” in 3D, all that is before it. That in turn will allow the user to control the objects on the screen by running his hands in the air, rather than touching the screen, as it is implemented in the now popular Touch Screen. That also allows you to get rid of the keyboard and mouse.

“This is a new level of interaction that no one has been able to do so far,” says Ramesh Raskar of the Massachusetts Institute of Technology Media Laboratory, in which the prototype was created. The project colleagues were Matthew Hirsch, Henry Holtzman, and Douglas Lanman from Brown University in Providence, Rhode Island.



BiDi (bidirectional) Screen , meaning “Bidirectional Screen” - allows users to control and interact with objects on the screen in three dimensions. It can also function as a 3D scanner. Ramesh also added:
“If you rotate an object in front of the screen, special software can“ stitch ”it into a single 3D object or image . ”
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Closer attention

The inspiration of Raskar and the Holzmann team were LCD panels from companies like Sharp and Planar Systems. But such displays usually have poor “vision”, like a camera without a lens, or a person with poor eyesight without glasses:

Lanman:
“They can clearly see objects that are in direct contact with the screen, but everything that is next is blurry. We changed the concept and our research and development allowed the screens to see the world in front of us more clearly . ”

Placing the tiny lenses of the sensors made it possible to achieve this effect, but the lens layer also negatively affected the image quality. Ultimately, Raskar and the Holzman team used a standard 20-inch screen to show how an ordinary LCD screen can act as an array of lenses.

The brightness of each pixel is controlled by a layer of liquid crystals, which are rotated to control the amount of light passing through the display. In BiDi, the team used the inverse of this function to control light passing in the opposite direction to the array of sensors under the screen.

When the screen "looks" around, most of the pixels on the liquid crystal is turned off. Thereby creating a small hole that is similar to the lens hole of the camera, focusing the external image on a thin translucent film a few centimeters inside the LCD display. These images are captured with a BiDi camera, and allow the device to “understand” what is going on. Unleashed potential of BiDi, allows, among other things, to generate stereoscopic images and to serve as a normal Touch-Screen.

The BIDI display was introduced a few weeks ago, at SIGGRAPH Asia 2009 .