The television has come a long way since it was first made commercially available in the 1930s. A few decades later, the color TV was developed from the earlier monochrome television technology.  The next big development was the introduction of digital TV and eventually High-Definition Television or HDTV in the 1990s.  We can now watch HDTV materials from different sources like terrestrial or satellite transmission, cable, IPTV and optical media such as DVD-HD or Blu Ray.  But what could be the next big thing in television technology?

One bold prediction from many quarters supporting the idea is 3D TV. Many though are skeptical and consider this technology as simply a marketing gimmick of television set manufacturers.  Others are also saying that 3D TV can never become mainstream and will remain an experimental thing.  It may take a number of years before we know who is correct but we will lose nothing if we try to understand now what 3D TV is and how it works.

Types of 3D Imaging Technologies

There are two major types of 3D imaging technologies. The first one is stereoscopy, which requires the use of special 3D glasses that can either be red-cyan glasses or polarized glasses. The other type is autostereoscopy that requires no 3D glasses. There are also other 3D technologies developed like holography, volumetric display and alternate-frame sequencing, but we will limit our discussion to stereoscopy and autostereoscopy. These are the ones that have the best chance of making it to our homes.

Stereoscopy (requires glasses)

In stereoscopy, a 3D illusion is created from a pair of 2D images. This is done by creating two different images that are similar but with minor perspective deviation with respect to the left and right eyes.  The cameras used in capturing the 2D images are mounted in such a way to simulate the views from the eyes.  In complementary color anaglyph, a pair of complementary color filters is used for each camera. The common color filters used are red and cyan. The red filter will allow only red information to pass through while the cyan filter will let only blue and green information to pass through. A pair of anaglyph 3D glasses, with red and cyan lenses, is used to recreate a 3D image from the two slightly different 2D images.

A better stereoscope technology than anaglyph 3D is polarized 3D. This is based on the natural characteristics of light, i.e. light waves are made up of horizontally and vertically polarized components. Similar to anaglyph 3D, special glasses are also needed to view polarized 3D images.  One lens allows only vertically polarized light to pass through, while the other lens allows only horizontally polarized light to pass through. In this way, the left and right eyes will see slightly different 2D images creating a perceived 3D image.

 Source: www.howstuffworks.com

Autostereoscopy

The main difference and advantage of autostereoscopy over stereoscopy is it does not require the use of special glasses in viewing 3D images. Depth of perception is processed and produced in the display device. Several technologies are used to achieve this. One is the use of lenticular lenses or parallax barrier in which the viewer sees almost similar images, with slightly different perspective, with each eye to recreate a 3D image. Another makes use of beamsplitter technique to create left and right eye images that are displayed sequentially. The LCD shutter of the display device redirects the intended picture frames to the left and right eyes so that they see only the relevant frames.

There are several autostereoscopic 3D technologies developed.  ome are experimental and some are being introduced in the consumer market. One of the most popular is WOW VX from Philips. It is based on the 2D-plus-depth technique that utilizes a greyscale depth map next to each 2D frame.  Other autostereoscopic 3D technologies developed were Holografika, Spatial View, i-Art, NextGen to name a few.

3D TV Standardization

In order for 3D TV to be available for home viewing, a set of standards needs to be adopted so that format battles will be avoided. This will also ensure that 3D TV displays from different vendors purchased by consumers will work with all 3D TV sources bounded by the standard. A move regarding this matter was initiated by companies consisting of content providers, appliance manufacturers and technology developers. These include Philips, DreamWorks and Disney. They asked SMPTE, the Society of Motion Picture and Television Engineers to formulate the standard.  In August 2008, SMPTE established a task force named 3D Home Display Formats Task Force. Its purpose is to set guidelines and lay the grounds for 3D content and programming to be displayed in 3D TV sets in the home. All delivery methods, be it via terrestrial, cable, satellite, Internet or via multimedia devices should be covered by the standard.

Future Developments and Trends

Even if the standards are set to bring 3D TV to the home, the infrastructure required is still a long way to go.  Current uncompressed HDTV materials need at least 1.5Gbps of bandwidth and a lot more will be required for 3D TV.This will necessitate the development of better and more efficient encoding and compression equipment. But this early, there are service providers bold enough to take the challenge and now gearing up in providing 3D TV service very soon. One is the UK satellite broadcaster BSkyB who will launch the service next year. Customers with HD-capable boxes can already receive 3D broadcast once it is available, but 3D capable display and 3D glasses will be required. Another pioneering 3D broadcaster is Telefonica from Brazil. They will launch a 3D IPTV service very soon. 3D capable displays will be required but their format is based on autostereocopy so there will be no need for special 3D glasses. Yes, no glasses!