Understanding the different 3D TV Formats

Prior to discussing the different 3D TV formats, I think it is important to comment on the fact that all TV makers made it clear that their 3D HDTVs will support the latest Blu-ray 3D^TM format.

This is extremely important at this early stage of deployment of 3D TV technology in the home. At least, we would not have a similar format war to the Blu ray - HD DVD we experienced a few years back.

This means that unlike early adopters who went for a 3D-ready HDTV with the hope of future-proofing their HDTV purchase between 2007 and 2009, buying a 3D TV now should still give you a usable 3D TV for the years to come.

Yet there is even more to multiple 3D TV format support. All TV makers confirmed that their 3D TVs will also be capable of processing the majority of 3D TV formats available today. In addition, both Sony and Samsung stated that the now established RealD's 3D technology capable of high quality 3D content - will be integrated into their line-ups of 3D TVs. And we expect that all other TV makers will be doing the same.

We also expect that all new 3D TVs will support DirecTV's and Playstation 3-D reduced resolution 3D TV formats. These are not full HD resolution 3D TV systems in that full HD 3D requires two full streams of 1080p content to display a full 1080p HD image to each eye in a field-sequential manner. If it were so, neither Sony's Playstation nor DirecTV's existing satellite receivers will be able to handle 3D TV through a simple firmware upgrade since the electronics inside are not designed to handle two simultaneous streams of 1080p content.

Most common 3D TV Formats explained

We have noted that DirecTV and Playstation 3D TV formats are not full resolution 3D.  DirecTV uses a 3D TV format referred to as Side-by-Side 3D where the horizontal resolution of the HD image is reduced by half in order to store the left eye and right eye images on a single frame. In the case of Playstation 3-D, it is the vertical resolution that is reduced by half as the images for the left and right eye are stored on top of each other in a single frame; this latter set-up is referred to as Top/Bottom 3D.

The 3D processor inside the 3D TV will expand the corresponding half frame image into a full-size image for each eye in accordance with the native resolution of the HDTV.

How the actual half frame is expanded into a full size image to cover the entire screen area may differ between different TV makers but systems may either work out the missing pixel data - like when upscaling image resolution to display a lower resolution image at the HDTV native screen resolution, or simply fill in adjacent lines in the case of top/bottom 3D systems and alternative pixels in the case of side-by-side 3D images.

In other words, the displayed images will still be field sequential but the 3D enjoyed in this manner will be of a lower resolution than that possible with Full HD 3D TV. Mind you, we expect that these lower resolution 3D TV format will still look great on the relatively small screen of the home HDTV.

In essence, these are not really different 3D TV formats in that the final presentation is just the same field sequential - with full size images despite of a lower resolution - being displayed for the left and right eye in a sequential order. Rather, this can be thought of in terms of a different resolution of the same 3D TV format, in a somewhat similar manner to the difference between 720p and 1080p HDTV.

This diagram - credit Cineramax Next Gen 4-D Cinema Systems - depicts how these different 3D TV formats store the left and right images; these are then processed so that irrespective of the way the information is stored in the 3D content, the final presentation would be a full size image for the left eye and a full size image for the right eye.

Instead, Blu ray 3D supports full 1080p content at source. This means that the images intended for the left and right eye are already at 1920 x 1080p pixel resolution at source. These images are then displayed in the usual field sequential order to render the effect of a 3-dimensional image.

The three 3D TV formats referred to above are not the only 3D TV imaging formats in use today. It is interesting however that all 3D TV systems in the home use some form of 3D glasses for the viewer to be able to see the two 2D images displayed by the system as a single 3D image. The type of 3D glasses to use however depends on the 3D technology in use.

For example, in the past, we have seen two-color Anaglyphic 3D  - viewed using anaglyph 3D glasses; these have two differently tinted lenses, often one in red and the other in cyan, though other anaglyphic 3D system come in either green and magenta, or yellow and blue. These 2-colored 3D glasses are used to combine two color-modified images - which when seen through the color correcting glasses, would supposedly produce a 3D image in the correct color.

But the result is inevitably a somewhat discolored image than that supported by the latest 3D TV technology using the latest field-sequential 3D TV formats.

We said that all present 3D TV formats use glasses; currently, there is no mass market technology for 3D in the home that lets a single TV displays both 2D and 3D content simultaneously without glasses.

However, 3D TV without glasses does exist but these are still prototypes. During CES 2009, Samsung presented a 3D 52-inch full high-definition television with an autostereoscopic display, where the image is doubled up so each eye perceives a slightly different view, and you get an illusion of depth perception without the need of 3D glasses.

But these displays are still extremely expensive to produce and they do have their downside as well. To view these displays, viewers have to stand at one of several points in the viewing area - otherwise the image will look doubled up and blurred. This is a major limitation in home 3D viewing. Some 3D prototypes without glasses incorporate a camera in the display to track the viewer's head and adjust the image parallax accordingly so that the viewer can sit anywhere. But as stated, these are prototypes with a number of drawbacks that still have to be overcome - apart from being very expensive for use as a mainstream 3D TV technology.