Polarized 3D system
This article needs additional citations for verification. (March 2010) |
A polarized 3D system uses polarization glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye (an example of stereoscopy).
To present stereoscopic images and films, two images are projected superimposed onto the same screen or display through different
Polarized 3D systems, and stereoscopy systems in general, commonly exhibit the
Types of polarised glasses
Linearly polarised glasses
To present a stereoscopic motion picture, two images are projected superimposed onto the same screen through
Circularly polarized glasses
To present a stereoscopic motion picture, two images are projected superimposed onto the same screen through
As shown in the figure, the
By rotating either the QWP or the LPF by 90 degrees about an axis perpendicular to its surface (i.e. parallel to the direction of propagation of the light wave), one may build an analyzing filter which blocks left-handed, rather than right-handed circularly polarized light. Rotating both the QWP and the LPF by the same angle does not change the behaviour of the analyzing filter.
System construction and examples
Polarized light reflected from an ordinary motion picture screen typically loses most of its polarization, but the loss is negligible if a silver screen or aluminized screen is used. This means that a pair of aligned DLP projectors, some polarizing filters, a silver screen, and a computer with a dual-head graphics card can be used to form a relatively high-cost (over US$10,000 in 2010) system for displaying stereoscopic 3D data simultaneously to a group of people wearing polarized glasses.[citation needed]
In the case of
Optical attachments can be added to traditional 35 mm projectors to adapt them for projecting film in the "over-and-under" format, in which each pair of images is stacked within one
When stereo images are to be presented to a single user, it is practical to construct an image combiner, using partially silvered mirrors and two image screens at right angles to one another. One image is seen directly through the angled mirror whilst the other is seen as a reflection. Polarized filters are attached to the image screens and appropriately angled filters are worn as glasses. A similar technique uses a single screen with an inverted upper image, viewed in a horizontal partial reflector, with an upright image presented below the reflector, again with appropriate polarizers.[original research?]
On TV and computer screens
Polarizing techniques are easier to apply with
In 2003 Keigo Iizuka discovered an inexpensive implementation of this principle on laptop computer displays using cellophane sheets.[6]
One can construct a low cost polarized projection system by using a computer with two projectors and an aluminium foil screen. The dull side of aluminium foil is brighter than most silver screens.[citation needed] This was demonstrated at PhraJomGlao University, Nônthaburi, Thailand, September 2009.
Health care
In optometry and ophthalmology, polarized glasses are used for various tests of binocular depth perception (i.e. stereopsis).
History
Polarized 3-D projection was demonstrated experimentally in the 1890s. The projectors used
Cardboard glasses with earpieces and larger filters were used to watch Bwana Devil, the feature-length color 3-D film that premiered on 26 November 1952 and ignited the brief but intense 3-D fad of the 1950s. The well-known Life magazine photo of an audience wearing 3-D glasses was one of a series taken at the premiere.[13][14] The film's title, imprinted on the earpieces, is plainly visible in high-resolution copies of those images. Imaginatively colorized versions have helped to spread the myth that the 3-D movies of the 1950s were projected by the anaglyph color filter method. In fact, during the 1950s anaglyph projection was used only for a few short films. Beginning in the 1970s, some 1950s 3-D feature films were re-released in anaglyph form so that they could be shown without special projection equipment. There was no commercial advantage in advertising the fact that it was not the original release format.
Polaroid filters in disposable cardboard frames were typical during the 1950s, but more comfortable plastic frames with somewhat larger filters, considerably more expensive for the theater owner, were also in use. Patrons were normally instructed to turn them in when leaving so that they could be sanitized and reissued, and it was not uncommon for ushers to be stationed at the exits to attempt to collect them from forgetful or souvenir-loving patrons.
Cardboard and plastic frames continued to co-exist during the following decades, with one or the other favored by a particular film distributor or theater or for a particular release. Specially imprinted or otherwise custom-made glasses were sometimes used. Some showings of
Linear polarization was standard into the 1980s and beyond.
In the 2000s, computer animation, digital projection, and the use of sophisticated IMAX 70 mm film projectors, have created an opportunity for a new wave of polarized 3D films.[15]
In the 2000s,
At
Advantages and disadvantages
This section needs additional citations for verification. (January 2017) |
Compared to
Particularly with the linear polarization schemes popular since the 1950s, the use of linear polarization meant that a level head was required for any sort of comfortable viewing; any effort to tilt the head sideways would result in the polarization failing, ghosting, and both eyes seeing both images. Circular polarization has alleviated this problem, allowing viewers to tilt their heads slightly (although any offset between the eye plane and the original camera plane will still interfere with the perception of depth).
Because neutral-gray linear-polarizing filters are easily manufactured, correct color rendition is possible. Circular-polarizing filters often have a slight brownish tint, which may be compensated for during projection.
Until 2011, home
) have introduced displays with horizontal polarizing stripes overlaying the screen. The stripes alternate polarization with each line. This permits using relatively inexpensive passive viewing glasses, similar to those for movies. The principal disadvantage is that each polarization can display only half as many scanning lines.Advantages
- Generally inexpensive.
- Glasses don't require power.
- Glasses don't require a transmitter to synchronize them with the display.
- No flickering.
- Lightweight.
- Comfortable.
Disadvantages
- The images for polarized glasses have to share the screen simultaneously in which full, native resolution is downgraded, compromising picture quality of both sides of the image delivered to each eye simultaneously[citation needed]. A full 1080p picture results from image fusion.[17][18] This disadvantage does not occur on projections where each pixel can contain information for both eyes.
- Associated with the headaches many people attribute to 3D viewing[citation needed].
- Narrow vertical viewing angles compared to Active shutter 3D [19]
See also
References
- ^ "Resolving the Vergence-Accommodation Conflict in Head-Mounted Displays" (PDF). 2022-09-22. Archived from the original (PDF) on 2022-09-22. Retrieved 2022-09-22.
- ^ Make Your own Stereo Pictures Julius B. Kaiser The Macmillan Company 1955 page 271 Archived 2011-02-26 at the Wayback Machine
- ^ Cowan, Matt (5 December 2007). "REAL D 3D Theatrical System" (PDF). European Digital Cinema Forum. Archived from the original (PDF) on 10 September 2016. Retrieved 5 April 2017.
- ^ "Sony – Market Professional". sony.com.
- ^ "Contact us – Technicolor Group". thomson.net.
- ^ "3D displays". Individual.utoronto.ca. Retrieved 2009-11-03.
- ^ Zone, Ray (2007). Stereoscopic Cinema and the Origins of 3-D Film, 1838–1952, University Press of Kentucky, pp. 64-66.
- ^ Zone, op. cit., p. 150
- ^ McElheny, Victor K (1998). Insisting On the Impossible, The Life of Edwin Land, Inventor of Instant Photography, Perseus Books, p. 114
- ^ Zone, op. cit., pp. 152-153
- ^ Note: some sources state that the Italian feature film Nozze Vagabonde, filmed in 3-D in 1936, was shown by polarized projection in that year, but no contemporary evidence of any kind has yet been presented to support the claim; other sources state that anaglyph projection was used, or that the 3-D version was never shown to the public at all. Sources agree that polarized projection was used for the German short Zum Greifen nah, filmed in 1936 with a single-strip 3-D system, but it was not shown to the public until 1937.
- ^ Zone, op. cit., p. 158 illustrates the viewers given out during the 1940 season of the Fair. The 1939 variety depicted the earlier model car head-on but the filters were identical.
- ^ Getty Images #2905087 One of several photographs taken by J. R. Eyerman at the Bwana Devil premiere.
- ^ Getty Images #50611221 One of several photographs taken by J. R. Eyerman at the Bwana Devil premiere.
- ^ Manjoo, Farhad. A look at Disney and Pixar's 3-D movie technology. 2008.04.09. Downloaded 2009.06.07
- ^ Price list showing paper linear polarized glasses at 3 for $2, anaglyph 2 for $1 http://www.berezin.com/3d/3dglasses.htm
- ^ "3D TV Display Technology Shoot-Out". displaymate.com.
- ^ http://hdguru.com/wp-content/uploads/2011/03/Intertek-LG-FPR-Report-.jpg [bare URL image file]
- ^ "Best TVs of 2016". cnet.com.