20-06-2013, 04:03 PM
3D TELEVISION
3D TELEVISION.docx (Size: 2.14 MB / Downloads: 19)
Abstract
Three-dimensional TV is expected to be the next revolution in the TV history. They implemented a 3D TV prototype system with real-time acquisition transmission, & 3D display of dynamic scenes. They developed a distributed scalable architecture to manage the high computation & bandwidth demands. 3D display shows high-resolution stereoscopic color images for multiple viewpoints without special glasses. This is first real time end-to-end 3D TV system with enough views & resolution to provide a truly immersive 3D experience.Japan plans to make this futuristic television a commercial reality by 2020as part of abroad national project that will bring together researchers from the government, technology companies and academia. The targeted "virtual reality" television would allow people to view high definitionimages in 3D from any angle, in addition to being able to touch and smell the objects being projected upwards from a screen to the floor.
INTRODUCTION
Three-dimensional TV is expected to be the next revolution in the TV history. They implemented a 3D TV prototype system with real-time acquisition transmission, & 3D display of dynamic scenes. They developed a distributed scalable architecture to manage the high computation & bandwidth demands. 3D display shows high-resolution stereoscopic color images for multiple viewpoints without special glasses. This is first real time end-to-end 3D TV system with enough views & resolution to provide a truly immersive 3D experience.
BASICS OF 3D TV
Human gains three-dimensional information from variety of cues. Two of the most important ones are binocular parallax & motion parallax.
Binocular Parallax
It means for any point you fixate the images on the two eyes must be slightly different. But the two different image so allow us to perceive a stable visual world. Binocular parallax defers to the ability of the eyes to see a solid object and a continuous surface behind that object even though the eyes see two different views.
Motion Parallax
It means information at the retina caused by relative movement of objects as the observer moves to the side (or his head moves sideways). Motion parallax varies depending on the distance of the observer from objects. The observer's movement also causes occlusion (covering of one object by another), and as movement changes so too does occlusion. This can give a powerful cue to the distance of objects from the observer.
Depth perception
It is the visual ability to perceive the world in three dimensions. It is a trait common to many higher animals. Depth perception allows the beholder to accurately gauge the distance to an object. The small distance between our eyes gives us stereoscopic depth perception[7]. The brain combines the two slightly different images into one 3D image. It works most effectively for distances up to 18 feet. For objects at a greater distance, our brain uses relative size and motion As shown in the figure, each eye captures its own view and the two separate images are sent on to the brain for processing. When the two images arrive simultaneously in the back of the brain, they are united into one picture. The mind combines the two images by matching up the similarities and adding in the small differences. The small differences between the two images add up to a big difference in the final picture ! The combined image is more than the sum of its parts. It is a three-dimensional stereo picture.
Transmission
Transmitting 16 uncompressed video streams with 1300X1030 resolution & 24 bits per pixel at 30 frames per seconds requires 14.4 Gblsec bandwidth, which is well beyond current broadcast capabilities. For compression & transmission o1 dynamic muitiview video data there are two basic design choices. Either the data from multiple cameras is compressed using spatial or spatio-temporal encoding, or each video stream is compressed individually using temporal encoding. The first option offers higher compression, since there is a lot of coherence between the views. However, it requires that a centralized processor compress multiple video streams. This compression-hub architecture is not scalable, since the addition of more views will eventually overwhelm the internal bandwidth of the encoder. So, they decided to use temporal encoding of individual video stream on distributed processors. This strategy has other advantages. Existing broadband protocols & compression standards do not need to be changed for immediate real world 3D TV experiments. This system can plug into today's digital TV broadcast infrastructure & co-exist in perfect harmony with 2D TV. There did not have access to digital broadcast equipment, they implemented the modified architecture as shown in figure 9.
3D DISPLAY
This is a brief explanation that we hope sorts out some of the confusion about the many 3D display options that are available today. We'll tell you how they work, and what the relative tradeoffs of each technique are. Those of you that are just interested in comparing different Liquid Crystal Shutter glasses techniques can skip to the section at the end. Of course, we are always happy to answer your questions personally, and point you to other leading experts in the field[4]. Figure shows a diagram of the multi-projector 3D displays with lenticular sheets.
CONCLUSION
Most of the key ideas for 3D TV systems presented in this paper have been known for decade, such as lenticular screens, multi projector 3D displays, and camera array for acquisition. This system is the first to provide enough view points and enough pixels per view points to produce an immersive and convincing 3D experience. Another area of future research is to improve the optical characteristic of the 3D display computationally. This concept is computational display. Another area of future research is precise color reproduction of natural scenes on multiview display.