3D – without the topping
Films in 3D are in fashion. Now, on the heels of such success in movie theaters, this form of presentation is now moving forward to conquer living rooms, too. At the consumer electronics fair IFA in Berlin (September 3-8, 2010), Fraunhofer researchers will be on hand in TecWatch Hall 8.1, showing how 3D television is possible without special glasses.
3D movies are a hit in movie theaters, but they’re also on the advance in home living rooms, too. Whether on the silver screen or the home theater, viewers need to wear shutter or polarized glasses if they want to be able get the three-dimensional – or, in experts’ jargon the stereoscopic – viewing experience. That changes, though, once the developments of the Fraunhofer Institute for Telecommunications, Heinrich-Hertz-Institut, HHI in Berlin are considered. Developers there have been working for several years to make a vision come true: 3D without the glasses. The mark of their success is a display they call "Free2C_digital."
"A 3D display is always based on the same principle," explains René de la Barré of HHI. "Two images are made visible, one for the left eye and one for the right." A sophisticated selected barrier sees to it that each eye views only the image content intended for it. To make this work, the viewer must hold his head absolutely still while viewing. That’s no fun for anyone. Therefore we have linked the 3D display with an additional technology: "electronic head-tracking." A camera sees the head and identifies the precise position of the eyes. This information is used to update the image content. Each movement of the head or eyes is registered, and the display is adjusted accordingly. The viewer always sees the perfect 3D image without having to put on an extra pair of glasses. "A process like ours that can do without glasses is referred to in the field as ‘autostereoscopic,’" de la Barré explains.
At the trade fair in Berlin, he and his team will be exhibiting another new development as well: a multimodal display in which the viewer can toggle back and forth between different display formats. There is a multiview mode in which multiple views of a scene are projected. This enables multiple persons to see an image in 3D. This can be switched to single-user mode, either automatically or at the touch of a button. Single-user mode requires just two picture views and delivers a more intense experience of depth. "Our display technology is designed so that the 3D televisions now being introduced can be watched without glasses," de la Barré describes. "That also solves a current problem. Because at the moment a 3D television picture cannot be displayed on a multiview display."
The reason: 3D television signals lack the needed additional information about depth. The current method for making 3D television recordings does not register depth information yet. The solution by HHI circumvents this lack of information. It uses just the two views broadcast – one picture each, left and right – and dynamically adjusts to the eye position of one or more viewers. "We have come up with a process that will enable us to provide these two views for even two or three viewers – instead of a single camera, we work with multiple cameras integrated into the display. We use them to track the eyes, tailoring the images perfectly for the different viewers," de la Barré observed.
The challenge with this autostereoscopic solution is to link multiview displays with eye-tracking and to deliver individually tailored picture content to each viewer in real time and free of distortion. One method patented by HHI adjusts picture content electronically on the display in keeping with the X-Y-Z positions of viewers’ eyes. This occurs with virtually no delay. This way, a 3D display can be continuously adjusted in all directions in line with the viewer’s position. The method also permits toggling back and forth between outputs of two or more views in response to the current number of viewers in the room.
Visitors to the IFA will have the chance to get a closer look at one of the first prototypes of this multimodal display.