3D Display Technology

What is 3D Display all about and how it works??

Overview:

 A stereo display (also 3D display) is a display device capable of conveying depth perception to the viewer by means of stereopsis for binocular vision.

Real 3D displays displaying an image in three full dimensions. The most notable difference to stereoscopic displays with only two 2D offset images is that the observer's head and eyes movement will increase information about the 3-dimensional objects being displayed.

As the cinematic experience radically changed from B&W to colour and the current 3D/4D/6D, so did the TVs in our homes. Bulky TV sets have given way to slim LCD and LEDs TVs—more recently, those equipped with 3D technology.

India is on the verge of 3D boom. The same kind of glasses as provided in movie theatres are required to enjoy a 3D movie in 3D effect on a 3D TV set. If you remove these glasses and watch the same movie with naked eyes, the incredible 3D experience would vanish and you would land up viewing distorted/blurred pictures.

The basic technique of stereo displays is to present offset images that are displayed separately to the left and right eye. Both of these 2D offset images are then combined in the brain to give the perception of 3D depth. Although the term "3D" is ubiquitously used, it is important to note that the presentation of dual 2D images is distinctly different from displaying an image in three full dimensions. The most notable difference to real 3D displays is that the observer's head and eyes movements will not increase information about the 3-dimensional objects being displayed. For example holographic displays do not have such limitations. Similar to how in sound reproduction it is not possible to recreate a full 3-dimensional sound field merely with two stereophonic speakers, it is likewise an overstatement of capability to refer to dual 2D images as being "3D". The accurate term "stereoscopic" is more cumbersome than the common misnomer "3D", which has been entrenched after many decades of unquestioned misuse. It is to note that although most stereoscopic displays do not qualify as real 3D display, all real 3D display are also stereoscopic displays because they meet the lower criteria as well.

Polarizing System:

 To present a stereoscopic picture, two images are projected superimposed onto the same screen through different polarizing filters. The viewer wears eyeglasses which also contain a pair of polarizing filters oriented differently (clockwise/counterclockwise with circular polarization or at 90 degree angles, usually 45 and 135 degrees,^[1] with linear polarization). As each filter passes only that light which is similarly polarized and blocks the light polarized differently, each eye sees a different image. This is used to produce a three-dimensional effect by projecting the same scene into both eyes, but depicted from slightly different perspectives. Additionally, since both lenses have the same color, people with one dominant eye (amblyopia), where one eye is used more, are able to see the 3D effect, previously negated by the separation of the two colors.

Circular polarization has an advantage over linear polarization, in that the viewer does not need to have their head upright and aligned with the screen for the polarization to work properly. With linear polarization, turning the glasses sideways causes the filters to go out of alignment with the screen filters causing the image to fade and for each eye to see the opposite frame more easily. For circular polarization, the polarizing effect works regardless of how the viewer's head is aligned with the screen such as tilted sideways, or even upside down. The left eye will still only see the image intended for it, and vice versa, without fading or crosstalk.

All types of polarization will result in a darkening of the displayed image and poorer contrast compared to non-3D images. Light from lamps is normally emitted as a random collection of polarizations, while a polarization filter only passes a fraction of the light. As a result the screen image is darker. This darkening can be compensated by increasing the brightness of the projector light source. If the initial polarization filter is inserted between the lamp and the image generation element, the light intensity striking the image element is not any higher than normal without the polarizing filter, and overall image contrast transmitted to the screen is not affected.

Fundamentals:

The 3D effect relies on creating an illusion of depth to the viewer. To understand what this means, simply watch your thumb with both your eyes, and then close one eye as you keep watching the thumb with the other eye. Now close this eye and open the previous one. Repeat this twice or thrice. You will see as if the thumb is shifting back and forth. This back and forth distance basically arises due to the depth created in visualising the thumb with different eyes.

This simple phenomenon is the basis for developing the 3D glasses. The movie screen actually displays two images. The glasses are designed to feed different images into our eyes. These let one of the images to enter one eye and the other image to enter the other eye. This is achieved using either of two ways: red/green or red/blue 3D glasses, and polarisation.

Red/green or red/blue 3D glasses
In this system, to produce the 3D effect, two images are displayed on the screen—one in red and the other in green or blue. The colour filters on the glasses allow only one image to enter each eye. This lends depth to the image, making it appear 3D to our brain.
However, the image quality with this method is not as good as with the polarised system. The reason is it somehow restricts some of the actual colours of the scene as it applies filtration by means of the colour itself.

 Application:

When correctly implemented, stereoscopic 3D video displays can provide significant benefits in many areas, including endoscopy and other medical imaging, remote-control vehicles and telemanipulators, stereo 3D CAD, molecular modelling, 3D computer graphics, 3D visualization, and video-based training.

3-D displays have become critical for many applications, including medical and scientific visualization, entertainment, flight simulation and training, tele-presence, engineering design, command and control, and other defence applications. This is the first incubator meeting organized by OSA that aims to bring together leading researchers and engineers from the 3D display fields, from academia, industry and government, to meet and discuss advances, challenges and opportunities, and future trends in 3D display research, development, and applications.

Advantages:

The technology of 3-dimensional (3D) image is now becoming the latest trend in the world of TVs and monitors alike. Here are a few advantages of 3D display

v        It seems that the 3D technology is offering something that is entirely new that people have never experienced before.

v     The 3D technology is a total innovation and this is often what makes it so interesting to a lot of people out there.

v       The main advantage of the 3D technology is that you can feel as if the objects you see on your TV or monitor screen come out of the screen heading your way offering you a sensational movie watching or gaming experience. Yet, besides that advantage, you will have to be aware of the

  Disadvantages:

Nowadays technology is advancing with each and every single second. Similarly, 3-Dtechnology was introduced in 2009 with the movie Avatar. Soon after this movie, the film industry started to make more 3-D movies since the audience was quite pleased but this has raised the question whether this new technology has its drawbacks or not. Below are a few but valid disadvantages of 3D technology that are brought into consideration.

v  Headache: Excessive viewing of 3D content can cause headaches. When people watch 3D for the very first time, their mind takes some time to adapt to this change and build the image in the viewer’s mind. Most of the people do not know about this fact since they do not experience headaches but there are people who have become disoriented and developed headaches after watching too many 3D movies.

v  Uncomfortably: When people want to enjoy this innovation of technology they want to experience it with fun while relaxing rather than being uncomfortable. The movies and the content that you watch in 3D has less brightness no matter whether you are using polarized or shutter glass technology.

v  No High Definition available: Showing 3D content in 1080i High Definition is not possible for standard Cable Television. This is the reason why 3D content is broadcasted in a lower resolution so that standard cable TV can support it.

v  3D movies not for all: Yes it is true that everyone cannot see 3D content. According to the research of College of Optometrists in Vision Development, about 5 to 10 percent people have this disease called stereo blindness. It is not a major fault of eyesight. People who have this disease can perfectly perceive everything which they normally see in daily life. It is just the matter of 3D movies which they cannot see. Instead, these 3D movies appear as if they were 2D to these people.