The International Telecommunications Union has set out a road map for 3D TV implementation. The initial levels defined by the ITU distinguish the different approaches to encoding stereoscopic images that are currently being employed and deployed. They also serve to demonstrate that stereoscopic 3D TV is not really three-dimensional, but simply adds further depth information to a two-dimensional representation. The ITU envisages that in 15-20 years there will be systems that will accurately mimic the way our eyes and brains perceive the visual world.
The ITU categorizes three successive generations or profiles of technology for 3D TV. The first, which is the focus of current systems, involves “plano-stereoscopic” presentation of two images viewed with special glasses. This permits an increased impression of depth in the picture, although the view remains the same irrespective of the head movement of the viewer.
Four different levels of presentation are considered for this generation of technology. The first level involves colour anaglyph, which is viewed using different coloured filters and is compatible with conventional displays, as with the amber and blue ColorCode system. The second encodes the left and right images in the same high-definition frame at half resolution, as for currently planned broadcast services. The third adds varying levels of resolution, as in Scalable Video Coding or SVC. The fourth level delivers two full high-definition images and takes advantage of their similarities to provide efficient compression, as with Multiview Video Coding or MVC, which is being adopted for Blu-ray discs.
A second generation of technology will support more than two views, allowing head movement to change the viewpoint, for a viewing experience that more closely mimics real life. Such systems could also remove the requirement to wear special glasses.
A third generation, using object wave technology, will record the amplitude, frequency and phase of light waves, more like a hologram. The ITU says this will reproduce almost completely the natural viewing environment, but notes that such systems are technically some 15-20 years away.
“This new ITU report establishes a clear framework for the development of new types of systems that will totally change the way we experience broadcast and multimedia content,” said Valery Timofeev of the ITU. “It maps out an exciting vision that won’t just change the look of entertainment, but open up a whole range of exciting new possibilities in sectors from education and healthcare to traffic management.”