NHK Shows 3D Video by Sending Full-HD Singnals to Each Eye

May 26, 2011
Tetsuo Nozawa, Nikkei Electronics
A demonstration of 3D video using a "dual stream" technology. The 3D glasses are a commercially-available active-shutter type.
A demonstration of 3D video using a "dual stream" technology. The 3D glasses are a commercially-available active-shutter type.
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NHK Science & Technology Research Laboratories had a demonstration of transmitting 3D video data via both broadcast and communication and displaying the video on a 3D-compatible TV.

The demonstration took place at Open House 2011, which opens for the public from May 26 to 29, 2011. The new technology was developed in collaboration with Nippon Telegraph and Telephone (NTT) Corp.

This transmission method for 3D video signals is a kind of technologies called "dual stream." Specifically, video for one of the right and left eyes is transmitted to a TV at home by airwaves, and video for the other eye is transmitted by a communication line. As a result, it becomes possible to transmit full HD equivalent video for each of the right and left eyes.

Currently, the 3D broadcasting method used for BS digital broadcasts, etc in Japan is the side-by-side method. It compresses images for each of the right and left eyes by about 50% (in terms of data amount) and stores both of them in one frame of full HD video. Then, they are decompressed on the side of TV.

Therefore, when 3D video is viewed with one eye, its resolution is lower than full HD. The greatest merit of the new method is that it does not cause this resolution reduction.

However, in 3D video transmission with a dual stream technology, signals transmitted via a communication line normally lag behind airwaves.

"We embed time stamp signals that are embedded in airwaves for synchronizing video and called PTS also in video data to be transmitted via a communication line," NHK Science & Technology Research Laboratories said. "And we synchronize images for the right and left eyes based on PTS on the side of TV."

In the demonstration, Panasonic Corp's 54-inch 3D TV, "TH-P54VT2," was used. But NHK Science & Technology Research Laboratories did not disclose whether the specifications of the TV were changed for the demonstration.

The company exhibited the new technology as one of the applications of the Hybridcast, a service that combines broadcast and communication. It transmits metadata to tablet computers such as the iPad based on contents being broadcast for TVs. The core technology of the service uses PTS (presentation time stamp) for synchronization synthesis of data being transmitted via different channels.