3D Technology in the cinemaand at home

Samantha Lusby@00231624

Jose Sarmiento Professional Broadcast Technology

Contents Pages

Introduction A brief history of 3D

1

Visual Depth Cues How we perceive 3D from a 2D perspective

2-3

Limits of 3D Range and discomfort 3D can bring

4

3D Glasses Brief look at origins of the glasses

Brief look at origins of the glasses

5-6

Anaglyph Glasses How do they work?

7-8

Linear Polarised Glasses How do they work?

9

Circularly Polarised Glasses How do they work?

10

3D at Home A brief history of the 3D TV

11

Active vs. Passive 3D How they work and the pros and cons

12-13

Conclusion The future of 3D

14

References 15-17

Bibliography 18-19

INTRODUCTION A brief history of 3D

3D technology has been around since the mid 19th Century when David Brewster invented the first stereoscopic still image camera called a stereoscope. Since then 3D technology has been constantly improving and changing to reach newer audiences. 3D however, only made its feature film debut in 1922 with ' The Power Of Love'. Since those early days of 3D, the technology has grown to become a successful form of entertainment for the general public in both the cinema and at home. But what is the science behind 3D exactly and how does this allow the general public to view it's effects?

Fig 1: Example of Anaglyph 3D

VISUAL DEPTH CUES How we perceive 3D from a 2D perspective

To understand how 3D works exactly, you first need to look at the relationship between the brain and eyes and how they rely on visual depth cues to allow the brain to judge the speed or the size of an item purely from a monoscopic perspective. This means an understanding of 3D can be achieved from a 2D perspective.

One of these various depth cues is known as a relative size cue. An example of this would be when you view a man and a skyscraper appearing as if they are same height. The brain will automatically tell you that one of these items is further away, thus creating the effect of depth.

Fig 2: Example of relative size cue.

Another cue is a texture gradient cue, this is simply where the same image is repeated over and over. Based on the fact the repeated image becomes smaller it again allows you to view distance.

A

Another type of visual cue is a motion parallax cue, a moving object can show its distance by its speed, the slower the object appears to be moving the further away it is. "This effect was intensively used in 2D games like 'Defender' in the 1980s and

Fig 3: Example of texture gradient cue

1990s. Fast moving sprites suggested close-up and slow-moving sprites were far away."

Fig 4: Example of motion parallax cue

LIMITS OF 3D Range and discomfort 3D can bring.

Since the brain is able to recognise these visual cues, it allows cinematographers a wide range of tricks to create a 3D world from a 2D perspective within the cinema with no limit on the depth created.

However the same cannot be said for stereoscopic viewing, this is because "stereoscopic perception hits a limit when objects are too far away to be seen differently by our eyes." Within the cinema this visual limit occurs in the 100-200 yard range, meaning that there is only so much 3D that can be achieved before the effect is lost and it begins to cause discomfort for the viewer as they try to process the image. This diagram shows the stereoscopic comfort zone within the cinema.

Grey: Invisible to audience

Red: Danger Zones – Strong muscular activity area.

Orange: Retinal rivalries zone. Causes discomfort

Green: Safe Zone – close to the screen.

3D GLASSES Brief look at origins of the glasses.

3D cannot be currently viewed without the use of stereoscopic eyewear. Over the

Fig 5: Example of the various stereoscopic zones within the cinema.

years the type of eyewear associated with 3D has changed as much as the science behind it. The most icon 3D eyewear are the old paper glasses with the red and cyan flitter, that everyone is familiar with . Yet the anaglyphic glasses have in fact been around since 1850 when Joseph D’Almeida and Louis Du Hauron began experimenting with 3D.

Fig 6: A pair of anaglyph glasses

Slowly more people began to gain an interest in 3D. In 1922 the first 3D film 'The Power of Love' was screened in Los Angles at the Ambassador Hotel Theatre. This film was shown using the anaglyphic glasses. However after the screening 3D disappeared until the golden age of 3D in the 50's.

"In the late 20th century, 3D has been falsely associated with cheap read-and-blue glasses. however, even in the 1950s, 3D used sunglass-like, neutral-grey filters,"

This meant that not all the 3D films during the golden age were viewed in a anaglyphic style, but instead used linear polarised lens, which look like a mix between the anaglyph glasses, with their cardboard frame and the RealD glasses we use today with their dark flittered lenses. These lenses provided a better viewing experience as the overall image appeared darker instead of having a coloured tint, which was experienced whilst trying to view a coloured film with anaglyph glasses. The linear lens glasses were used in the 50’s and 80's but have since disappeared from most mainstream cinemas.

The most recent form of 3D eyewear appeared during the early days of the 3D renaissance in early 2000's and began growing more and more popular since then. The latest 3D eyewear has taken a step forward from it's predecessors and discards the old cardboard frames for a look much more similar to regular eye wear. The lens in the latest 3D eyewear work in a completely different way to the earlier versions as these glasses work with circularly polarised lens.

ANAGLYPH GLASSESHow do they work?

Since the anaglyph lenses were some of the first main stream eyewear into viewing 3D the science behind them is simpler than the most current technologies used to view 3D in the cinema.

Firstly there is the original image which than has two images superimposed on top of it. These two extra images are the same as the original one but taken from a slightly different angle. This is to coincide with normal human perception of objects, this was

originally achieved by placing "two cameras next to each other where the lenses are about 3 inches apart. This mimics the natural space between your eyes."

The most iconic colours for the anaglyph lens are red and cyan, however there are more visual colour pairings such as, " red and green, and the less-used yellow and blue and magenta and green." The red and cyan lens will be used to explain the 3D example.

Due to the different filters on each eye the brain perceives the different colours on the image in different ways. Through the cyan filter our brain views the cyan areas of the image as white, whilst the red areas are viewed as black. The opposite effect is seen through the red flitter, any natural blacks and whites on the original image are viewed normally and are not effected by the lens. Next the brain blends the two separate images into one seeing the difference in colour as distance, thus creating the 3D image.

The reason the red and cyan lens work so well together is because they "cover opposite

Fig 7: Example of anaglyph image

Fig 8: Explanation of anaglyphic 3D.

ends of the visible light spectrum. Thus the black and white apparent differences."

LINEAR POLARISED GLASSESHow do they work?

Linear polarised glasses were around in cinema about the same time as the anaglyph lens of the 1950s. However the science behind the linear lenses is different to that of anaglyphs.

Fig 9: A pair of linear glasses

In a similar style to anaglyphic 3D, linear 3D is first viewed by having two images superimposed onto one screen but from slightly different angles. However this is the only similarity between linear and anaglyphic 3D.

The two images are first projected onto a silver screen, this is to preserve the polarised effect. When the image is projected it passes through orthogonal polarising filters, the filters are spaced 135 degrees to the right and 45 degrees to the left. You as a viewer will wear the glasses, which the lens are filtered in the same way.

When the light passes through the filter, the filter will block any light that does not match the direction of the filter, meaning only a select amount of light passes through. This turns the light into a linear form by sending out only the left and right channels separately. Since the glasses are filtered in the same way as the projector. Your eyes will only pick up one of the two images. It is at this stage that the brain again takes over and blends these two separate images into one creating the 3D effect.

CIRCULARLY POLARISED GLASSES How do they work?

Fig 10: Science behind linear polarisation

Circularly polarized glasses are the most current eyewear for the cinema. They work by yet again superimposing two images from a slightly different perspective , which the brain fuses to make the 3D effect.

This time the light from the projector passes through a quarter-wave plate (QWP), this filter is positioned in the opposite direction of the glasses. Once the circular light passes through the QWP it becomes a linear light, which after passing through a linear polariser, then begins to work in a similar fashion as linear polarised lenses. This means that the left filter blocks out the right image and vice versa. This helps to achieve the 3D effect.

3D AT HOMEA brief history of the 3D TV.

With many cinema adapting their equipment to allow more 3D films to be shown, the technology also began to change in the home to allow for the 3D viewing experience

Fig 11: A pair of circularly polarised glasses

Fig 12: Science behind circular polarisation

to continue.

2010 saw the release of some of the first 3D televisions in the home. Many people believe that these were the first 3D television sets, however this is in fact incorrect . The first prototype 3D television was created by the inventor behind television, John

Loige Baird. In 1928 Mr Baird demonstrated his stereoscopic television.

After that however the development in 3D technology seems so be set aside whilst other technologies and improvements began such as the introduction of colour to television.

The basics of 3D television were primarily developed in the 80s and 90s. This progress in stereoscopic televisions was made by "three companies: StereoGraphics, Tektronix and VRex." These companies were some of the first to develop the eyewear associated with 3D viewing.

One of the reasons why 3D technology took so long to reach the general population , despite being around so long is because; there was no set format that 3D could be broadcast in, due to NTSC, PAL and SECAM following different protocols thus delaying the 3D technology until HD came along. This allowed some basic rules to be set which then paved the way for 3D to develop.

Like in the cinema, 3D can not be viewed without glasses. It should also be said that, “the prior dominant display technology, the cathode ray tube, or CRT, was a better vehicle for the viewing of field-sequential stereoscopic TV than the modern pervasive liquid crystal display screen."

ACTIVE VS. PASSIVE 3DHow they work and the pros and cons.

Since it is currently not an option to view 3D televisions in an autostereoscopic

Fig 13: Baird’s 3D Television

manner. Glasses must be used to view the 3D effect. At this current time there are only two types of glasses available for viewing 3D in the home, these are active and passive. One of the main differences between active and passive 3D is that active 3D requires a battery to operate the glasses and Bluetooth for it to sync with the television.

Active glasses work by having the images on the television switch quickly between the left and right image simultaneously. The glasses then begin to flicker between the left and the right eye at the same speed they are shown on the television. This is where the wireless connection between the TV and glasses

works as it tells the glasses when to open and close each shutter on the glasses. Due to the images continuously switching between the left and right channel the overall frame rate of the images needs to increase from 24 to 48 frames per seconds to allow the image to be viewed. By quickly alternating between the left and the right channels and doubling the frame rate the 3D effect is achieved.

Passive glasses work in a much simpler way compared to the active glasses. Passive glasses work in a similar way to the polarised lenses used in the cinemas. First there are two images superimposed on the screen, showing the same image from slightly different angles. the lens on the glasses are then filtered in opposite directions. This is done so the filters pick up the corresponding image to the filter. By viewing the same image from slightly different perspectives the 3D image is created.

There are many differences between active and passive 3D:

Fig 14: A pair of Panasonic shutter glasses

Fig 15: A pair of LG passive glasses

Fig 16: A table to show differences between active and passive 3D

CONCLUSIONThe future of 3D

It seems many films are changing to meet a new market by becoming 3D, including older titles such as “Beauty and the Beast” and “Titanic”.

Nowadays 3D is not just an experience at the cinema, it's an experience in the home as well. Since 3D channels are now appearing such as Sky 3D, this proves how the 3D experience is being brought into the home. Yet to prolong the 3D experience in the home many game developers have begun releasing title games with a 3D option. At this current time we all know from experience that the only way to view stereoscopic 3D is through the use of stereoscopic glasses .

However various developers are beginning to try and produce autostereoscopic viewing which is the ability to view 3D without the need of the glasses. The most current example of this on the market would be the Nintendo 3DS. However this device has not taken into account the safety distance allowed for 3D as within it's first year alone Nintendo has received many complaints that, "Nintendo's autostereoscopic technology causes dizziness, headaches and nausea."

Fig 17: A Nintendo 3DS

Autostereoscopic viewing still has a long way to go in the development stages, but considering that the 3D renaissance has only been around for a few years it seems that 3D is going to be around in the entertainment industry for quite some time.

References

- (2009) Fig 7: Example of anaglyph image. [image online] Available at: http://www.psy.jhu.edu/~spring200_206/depth_section07_QALMRIa.pdf [Accessed: 27th December 2011].

- (2009) Fig 8: Explanation of anaglyph 3D. [image online] Available at: http://www.psy.jhu.edu/~spring200_206/depth_section07_QALMRIa.pdf [Accessed: 27th December 2011].

3D Active Shutter Glasses (n.d.) Fig 14: A pair of Panasonic shutter glasses. [image online] Available at: http://www.3dactiveshutterglasses.com/ [Accessed: 28th December 2011].

3D Movie Making: Steroscopic Digital Cinema from Script to Screen . (2009) Fig 1: Example of Anaglyph 3D [DVD] United States of America : Elsevier .

3D TV Technology (n.d.) Fig 16: A table to show the difference between active and passive 3D. [image online] Available at: http://www.3dtvtechnology.org.uk/passive-versus-active [Accessed: 29th December 2011].

3dguy.tv (2009) What are 3D Glasses and what is Anaglyph?, [online] "two cameras next to each other where the lenses are about 3 inches apart. This mimics the natural space between your eyes." Available at: http://3dguy.tv/tag/history-of-anaglyph/ [Accessed: 20th December 2011].

3dguy.tv (2009) What are 3D Glasses and what is Anaglyph?, [online] "cover opposite ends of the visible light spectrum. Thus the black and white apparent differences." Available at: http://3dguy.tv/tag/history-of-anaglyph/ [Accessed: 20th December 2011].

3dham (n.d.) Fig 9: A pair of linear glasses. [image online] Available at: http://www.3dham.com/miscpics/mann3dglasses.jpg [Accessed: 28th November 2011].

AndrA Gustavo (2006) Fig 2: Example of relative size cue. [image online] Available at: http://www.moillusions.com/2006/08/leaning-tower-of-pisa.html [Accessed: 28th November 2011].

Baird Television (n.d.) Fig 13: Baird's 3D Television . [image online] Available at: http://www.bairdtelevision.com/stereo.html [Accessed: 29th November 2011].

Bernard Mendiburu (2009) Fig 4: Example of motion parallax cue. [image online] Available at: http://www.3dtv.fr/NAB09_3D-Tutorial_BernardMendiburu.pdf [Accessed: 28th November 2011].

Bernard Mendiburu (2009) Fig 5: Example of various stereoscopic zones within the cinema. [image online] Available at: http://www.3dtv.fr/NAB09_3D-Tutorial_BernardMendiburu.pdf [Accessed: 28th November 2011].

Bob Mellish (n.d.) Fig 10: Science behind linear polarisation . [image online] Available at: http://en.wikipedia.org/wiki/File:Wire-grid-polarizer.svg [Accessed: 28th

November 2011].

Business Insider (2010) Fig 17: A Nintendo 3DS. [image online] Available at: http://www.businessinsider.com/3d-2010-6?op=1 [Accessed: 29th December 2011].

Digital Trends (2011) Fig 15: A pair of LG passive glasses. [image online] Available at: http://www.digitaltrends.com/home-theater/active-vs-passive-3d-tv-technology-whats-the-difference/ [Accessed: 28th December 2011].

Mendiburu, B. (2009) 3D Movie Making: Steroscopic Digital Cinema from Script to Screen , United States of America : Elsevier , p.2. "In the late 20th century, 3d has been falsely associated with cheap read-and-blue glasses. However, even in the 1950s, 3D used sunglass-like, neutral-gray filters."

Mendiburu, B. (2009) 3D Movie Making: Steroscopic Digital Cinema from Script to Screen , United States of America : Elsevier , p.21. "stereoscopic perception hits a limit when objects are too far away to be seen differently by our eyes."

Mendiburu, B. (2009) 3D Movie Making: Steroscopic Digital Cinema from Script to Screen , United States of America : Elsevier , p.16-17. "This effect was intensively used in 2D games like 'Defender' in the 1980s and 1990s. Fast moving sprites suggessted close-up and slow-moving sprites were far away."

Mendiburu, B. (2012) 3D TV and 3D Cinema: Tools and Processes for Creative Steroscopy, United States of America : Elsevier , p.xiii. "three companies: StereoGraphics, Tektronix and VRex."

Mendiburu, B. (2012) 3D TV and 3D Cinema: Tools and Processes for Creative Steroscopy, United States of America : Elsevier , p.xiii. "Curiously, though, the prior dominant display technology, the cathode ray tube, or CRT, was a better vehicle for the viewing of field-sequential stereoscopic TV than the modern pervasive liquid crystal display screen."

Mendiburu, B. (2009) 3D Movie Making: Steroscopic Digital Cinema from Script to Screen , United States of America : Elsevier , p.190. " red and green, and the less-used yellow and blue and magenta and green."

Midori iro (2007) Fig 11: A pair of circularly polarised glasses . [image online] Available at: http://upload.wikimedia.org/wikipedia/commons/4/47/REALD.JPG [Accessed: 28th November 2011].

The Tech Herald (2011) Nintendo 3DS comes with free headaches, dizziness, and nausea, [online] "Nintendo's autostereoscopic technology causes dizziness, headaches and nausea." Available at: http://www.thetechherald.com/articles/Nintendo-3DS-comes-with-free-headaches-dizziness-and-nausea [Accessed: 30th November 2011].

Troy (Film) (2009) Fig 3: Example of texture gradient cue. [image online] Available at: http://www.dvdbeaver.com/film2/DVDReviews32/a%20troy%20dc%20blu-ray/16_Troy_BD_ships.jpg [Accessed: 28th November 2011].

Wikipedia (2007) Fig 6: A pair of anaglyph glasses . [image online] Available at: http://upload.wikimedia.org/wikipedia/commons/e/e7/Anaglyph_glasses.png [Accessed: 28th November 2011].

Wikipedia (n.d.) Fig 12: Science behind circularly polarisation . [image online] Available at: http://upload.wikimedia.org/wikipedia/commons/8/82/Circular.Polarization.Circularly.Polarized.Light_Circular.Polarizer_Passing.Left.Handed.Helix.View.svg [Accessed: 28th November 2011].

Bibliography

Books

Mendiburu, B. (2009) 3D Movie Making: Steroscopic Digital Cinema from Script to Screen , United States of America : Elsevier , p.2. p.21. p.16-17. p.190

Mendiburu, B. (2012) 3D TV and 3D Cinema: Tools and Processes for Creative Steroscopy, United States of America : Elsevier , p.xiii.

DVD

3D Movie Making: Steroscopic Digital Cinema from Script to Screen . (2009), [DVD] United States of America : Elsevier .

Websites

http://3dguy.tv/tag/history-of-anaglyph/

http://en.wikipedia.org/wiki/File:Wire-grid-polarizer.svg

http://upload.wikimedia.org/wikipedia/commons/4/47/REALD.JPG

http://upload.wikimedia.org/wikipedia/commons/8/82/Circular.Polarization.Circularly.Polarized.Light_Circular.Polarizer_Passing.Left.Handed.Helix.View.svg

http://upload.wikimedia.org/wikipedia/commons/e/e7/Anaglyph_glasses.png

http://www.3dactiveshutterglasses.com/

http://www.3dham.com/miscpics/mann3dglasses.jpg

http://www.3dtv.fr/NAB09_3D-Tutorial_BernardMendiburu.pdf

http://www.3dtvtechnology.org.uk/passive-versus-active

http://www.bairdtelevision.com/stereo.html

http://www.businessinsider.com/3d-2010-6?op=1

http://www.digitaltrends.com/home-theater/active-vs-passive-3d-tv-technology-whats-the-difference/

http://www.dvdbeaver.com/film2/DVDReviews32/a%20troy%20dc%20blu-ray/16_Troy_BD_ships.jpg

http://www.moillusions.com/2006/08/leaning-tower-of-pisa.html

http://www.psy.jhu.edu/~spring200_206/depth_section07_QALMRIa.pdf

http://www.thetechherald.com/articles/Nintendo-3DS-comes-with-free-headaches-dizziness-and-nausea