CONTENT Introduction History How we see 3D How to create 3D ? Common 3D display technique Viewing through glass Anaglyphic 3D Polarization 3D Active glasses Auto stereoscopic display Lenticular lenses Parallax barrier Architecture of 3D TV Transmission 3D display Application Advantages and disadvantage
INTRODUCTION A 3D television is a television that employs techniques of 3D presentation, such as stereoscopic capture, multi- view capture, or 2D plus depth, and a 3D display a special viewing device to project a television program into a realistic three-dimensional field. Three dimensional TV is expected to be next revolution in the TV history.
HISTORY The stereoscope was first invented by Sir Charles Wheatstone in 1838. Stereoscopic 3D television was demonstrated for the first time on 10 August 1928. A stereoscope is a device for viewing a stereoscopic pair of separate images, depicting left-eye and right-eye views of the same scene, as a single three-dimensional image.
HOW WE SEE 3D Basic principle tricking our dumb, binocular brain into interpreting a 2Dimage into one with depth.A key part of this process is binocular disparity. It means each eye has a slightly different viewpoint. When an object is far away, the light traveling to one eye is parallel with the light traveling to the other eye. But as an object gets closer, the lines are no longer parallel --they converge and our eyes shift to compensate.
HOW TO CREATE 3D? It involves the usage of two cameras (or a camera having two lenses), placed side by side with the center of their lenses spaced approximately and ideally, the same distance as the space between our eyes. Both cameras record in sync and the resulting left and right eye videos or images are then edited and presented to the viewer (in cinemas) via different techniques.
COMMON 3D DISPLAY TECHNOLOGY Projecting stereoscopic image pairs to the viewer include: Passive glass: Anaglyphic 3D (with red-blue glasses) Polarization 3D (with polarized glasses) Active glass: Alternate-frame sequencing Auto stereoscopic displays (without glasses)
VIEWING THROUGH GLASSES Two sets of images are meant to be seen by only particular eye. Hence each eye can only see one set of images, your brain interprets this to mean that both eyes are looking at the same object. Thats what creates the illusion of depth.
ANAGLYPHIC 3D RED-BLUE GLASSES There are two sets of images slightly offset from one another. One will have a blue tint to it and the other will have a reddish hue. Anaglyph glasses use two different color lenses to filter the images you look at on the television screen. The two most common colors used are red and blue.
POLARIZATION 3D POLARIZED GLASSES Light waves of two images are projected at certain angles. Each lens only allows light to pass through that is polarized in a compatible way. It is more popular than anaglyph glasses because the polarization dont distort the color of the image. Hence it is popular in projector based display.
ACTIVE GLASSES ALTERNATE-FRAME SEQUENCING An active glasses system alternates between the two sets of images at very high speeds. Active glasses have infrared (IR)sensors. As the 3-D content appears on the screen, the picture alternates between two sets of the same image.
ADVANTAGE OF ACTIVE GLASSES OVER PASSIVE GLASSES Its easier to present 3-D in HD content using active glasses than with passive glasses. Thats because with a passive glass system, the television has to display two sets of images at the same time. An active glasses system alternates between that two sets of images at very high speeds--its less information for the television to handle at any particular moment.
BUT STILL HAVE A PROBLEM WITH THOSE GLASSES?Stereoscopic method leads to problems: The glasses are really cumbersome and expensive, and you dont want to accidentally sit on one or lose it. And what to do when we dont have enough lenses. Plus, it takes away the simplicity of television as it stands today, where you simply hit the remote and start watching. Also, without the glasses, any 3D content is completely unusable.
AUTO STEREOSCOPIC DISPLAY Two main technologies that rely on it: Lenticular lenses Parallax barrier
LENTICULAR LENSES Basically A lenticular lens is an array of magnifying or directing lenses, designed so that when viewed from slightly different angles, different images are magnified. Lenticulars are tiny lenses on the base side of a special film. The screen displays two sets of the same image. The lenses direct the light from the images to your eyes each eye sees only one image. It creates a particular space from which images can seen clearly called ‘sweet spot’.
PARALLAX BARRIER On a 3D screen, a very fine grating, called a "parallax barrier", is placed in front of the LCD screen. The parallax barrier is a fine grating of liquid crystals placed in front of the screen, with slits in it that correspond to certain columns of pixels of the screen. It does the job of the polarizing glasses, directing light from each image slightly in different direction so that at a so-called "sweet spot" about 30 inches in front of the screen the two images are separated just enough that the brain will create a composite 3D image.
ADVANTAGE OF PARALLAX BARRIER OVER LENTICULAR LENSES parallax barrier can be switched on and off with ease (one button on the remote is all it would take), allowing the TV to be used for 2D or3D viewing. So on a computer monitor, you could play video games in full 3D and then easily switch to 2D mode for your work requirements.
TRANSMISSIONGigabit Ethernet A transmission technology, enables super net to deliver enhanced network performance.
APPLICATION OF 3D TV video games TV applications for physicists, scientists, and engineers could also be extremely useful. Richer ,Lifelike and entertaining experience than 2D TV for home users. Future use in mobile.
CONCLUSION Thus we have seen various technologies used for 3D imaging and viewing. We also explained technology of 3D TV, discussed various aspects and features of 3D TV. Another area of future research is precise colour reproduction of natural scenes on multiview displays. In future we will be able to touch and smell the objects being projected from a screen to the viewers.