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 Two pairs of RealD glasses demonstrating the polarization effect | |
| Type | 3D projection technology |
|---|---|
| Manufacturer | RealD |
| Website | http://www.reald.com  |
RealD 3D is a digital stereoscopic projection technology made and sold by RealD. It is currently the most widely used technology for watching 3D films in theaters. [1] Worldwide, RealD 3D is installed in more than 26,500 auditoriums by approximately 1,200 exhibitors in 72 countries as of June 2015. [2]
RealD 3D cinema technology is a polarized 3D system that uses circularly polarized light to produce stereoscopic image projection. The advantage of circular polarization over linear polarization is that viewers are able to tilt their head and look about the theater naturally without seeing double or darkened images. [3] However, as with other systems, any significant head tilt will result in incorrect parallax and prevent the brain from correctly fusing the stereoscopic images.
The high-resolution, digital cinema grade video projector alternately projects right-eye frames and left-eye frames, switching between them 144 times per second. [3] The projector is either a Texas Instruments Digital Light Processing device or Sony's reflective LCOS (liquid crystal on silicon). A push-pull electro-optical liquid crystal modulator called a ZScreen is placed immediately in front of the projector lens to alternately polarize each frame. It circularly polarizes the frames clockwise for the right eye and counter-clockwise for the left eye. [4] The audience wears circularly polarized glasses that have oppositely polarized lenses that ensures each eye sees only its designated frame. In RealD Cinema, each frame is projected three times to reduce flicker, a system called triple flash. The source video is usually produced at 24 frames per second per eye (total 48 frames/s), which may result in subtle ghosting and stuttering on horizontal camera movements. A silver screen is used to maintain the light polarization upon reflection and to reduce reflection loss to counter some of the significant light loss due to polarization filter absorption. The result is a 3D pictures that seems to extend behind and in front of the screen itself. [5]
Polarization is a property of transverse waves which specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave. A simple example of a polarized transverse wave is vibrations traveling along a taut string (see image); for example, in a musical instrument like a guitar string. Depending on how the string is plucked, the vibrations can be in a vertical direction, horizontal direction, or at any angle perpendicular to the string. In contrast, in longitudinal waves, such as sound waves in a liquid or gas, the displacement of the particles in the oscillation is always in the direction of propagation, so these waves do not exhibit polarization. Transverse waves that exhibit polarization include electromagnetic waves such as light and radio waves, gravitational waves, and transverse sound waves in solids.
3D films are motion pictures made to give an illusion of three-dimensional solidity, usually with the help of special glasses worn by viewers. They have existed in some form since 1915, but had been largely relegated to a niche in the motion picture industry because of the costly hardware and processes required to produce and display a 3D film, and the lack of a standardized format for all segments of the entertainment business. Nonetheless, 3D films were prominently featured in the 1950s in American cinema, and later experienced a worldwide resurgence in the 1980s and 1990s driven by IMAX high-end theaters and Disney-themed venues. 3D films became increasingly successful throughout the 2000s, peaking with the success of 3D presentations of Avatar in December 2009, after which 3D films again decreased in popularity. Certain directors have also taken more experimental approaches to 3D filmmaking, most notably celebrated auteur Jean-Luc Godard in his film Goodbye to Language.
An LCD projector is a type of video projector for displaying video, images or computer data on a screen or other flat surface. It is a modern equivalent of the slide projector or overhead projector. To display images, LCD projectors typically send light from a metal-halide lamp through a prism or series of dichroic filters that separates light to three polysilicon panels – one each for the red, green and blue components of the video signal. As polarized light passes through the panels, individual pixels can be opened to allow light to pass or closed to block the light. The combination of open and closed pixels can produce a wide range of colors and shades in the projected image.
Liquid crystal on silicon is a miniaturized reflective active-matrix liquid-crystal display or "microdisplay" using a liquid crystal layer on top of a silicon backplane. It is also known as a spatial light modulator. LCoS initially was developed for projection televisions, but has since found additional uses in wavelength selective switching, structured illumination, near-eye displays and optical pulse shaping.
Digital Light Processing (DLP) is a set of chipsets based on optical micro-electro-mechanical technology that uses a digital micromirror device. It was originally developed in 1987 by Larry Hornbeck of Texas Instruments. While the DLP imaging device was invented by Texas Instruments, the first DLP-based projector was introduced by Digital Projection Ltd in 1997. Digital Projection and Texas Instruments were both awarded Emmy Awards in 1998 for the DLP projector technology. DLP is used in a variety of display applications from traditional static displays to interactive displays and also non-traditional embedded applications including medical, security, and industrial uses.
A 3D display is a display device capable of conveying depth to the viewer. Many 3D displays are stereoscopic displays, which produce a basic 3D effect by means of stereopsis, but can cause eye strain and visual fatigue. Newer 3D displays such as holographic and light field displays produce a more realistic 3D effect by combining stereopsis and accurate focal length for the displayed content. Newer 3D displays in this manner cause less visual fatigue than classical stereoscopic displays.
An active shutter 3D system is a technique of displaying stereoscopic 3D images. It works by only presenting the image intended for the left eye while blocking the right eye's view, then presenting the right-eye image while blocking the left eye, and repeating this so rapidly that the interruptions do not interfere with the perceived fusion of the two images into a single 3D image.
A polarized 3D system uses polarization glasses to create the illusion of three-dimensional images by restricting the light that reaches each eye.
Anaglyph 3D is the stereoscopic 3D effect achieved by means of encoding each eye's image using filters of different colors, typically red and cyan. Anaglyph 3D images contain two differently filtered colored images, one for each eye. When viewed through the "color-coded" "anaglyph glasses", each of the two images reaches the eye it's intended for, revealing an integrated stereoscopic image. The visual cortex of the brain fuses this into the perception of a three-dimensional scene or composition.
A vectograph is a type of stereoscopic print or transparency viewed by using the polarized 3D glasses most commonly associated with projected 3D motion pictures.
A polarizer or polariser is an optical filter that lets light waves of a specific polarization pass through while blocking light waves of other polarizations. It can filter a beam of light of undefined or mixed polarization into a beam of well-defined polarization, known as polarized light. Polarizers are used in many optical techniques and instruments. Polarizers find applications in photography and LCD technology. In photography, a polarizing filter can be used to filter out reflections.
Infitec GmbH is a family-owned company based in Gerstetten that develops, produces and markets products for the projection of 3D content. The registered name INFITEC is an acronym of Interference Filter Technology, which was invented and patented by the founder of the company, Helmut Jorke.
Teleview was a system for projecting stereoscopic motion pictures invented by Laurens Hammond, best known as the inventor of the Hammond organ. It made its public debut on 27 December 1922 at the Selwyn Theatre in New York City, the only theater ever equipped with the system. The program included several short films, a live presentation of projected 3D shadows, and the 95-minute feature film M.A.R.S., later re-released in 2D as Radio-Mania.
Leonard Lipton was an American author, filmmaker, lyricist and inventor. At age 19, Lipton wrote the poem that became the basis for the lyrics to the song "Puff, the Magic Dragon". He wrote books on independent filmmaking and become a pioneer in the field of projected three-dimensional imagery. Leonard Lipton developed 3D cinema technology that is used in RealD 3D cinemas. His technology is used to show 3D films on more than 30,000 theater screens worldwide.
TDVision Systems, Inc., was a company that designed products and system architectures for stereoscopic video coding, stereoscopic video games, and head mounted displays. The company was founded by Manuel Gutierrez Novelo and Isidoro Pessah in Mexico in 2001 and moved to the United States in 2004.
Dolby 3D is a marketing name for a system from Dolby Laboratories, Inc. to show three-dimensional motion pictures in a digital cinema.
MasterImage 3D is a company that develops stereoscopic 3D systems for theaters, and auto-stereoscopic 3D displays for mobile devices.
ZScreen is a push-pull electro-optical liquid crystal modulator that is placed immediately in front of the projector lens or computer screen to alternately polarize the light from each video frame. It circularly polarizes the frames clockwise for the right eye and counterclockwise for the left eye.
FPR is a technology promoted by LG that is employed in its line of 3D televisions based on circular polarization. It shows left and right images through different patterns in a circular polarizer. Left/right polarized glasses allow the left and right images to then be seen by the left and right eyes separately. Both images are combined in the brain and generate the 3D effect. The FPR technology uses the precise film which polarizes different pixels differently to show a different image for each eye. FPR 3D tech is said to deliver a brighter screen with less cross talk, less ghosting, and no flickering.
The history of film technology traces the development of techniques for the recording, construction and presentation of motion pictures. When the film medium came about in the 19th century, there already was a centuries old tradition of screening moving images through shadow play and the magic lantern that were very popular with audiences in many parts of the world. Especially the magic lantern influenced much of the projection technology, exhibition practices and cultural implementation of film. Between 1825 and 1840, the relevant technologies of stroboscopic animation, photography and stereoscopy were introduced. For much of the rest of the century, many engineers and inventors tried to combine all these new technologies and the much older technique of projection to create a complete illusion or a complete documentation of reality. Colour photography was usually included in these ambitions and the introduction of the phonograph in 1877 seemed to promise the addition of synchronized sound recordings. Between 1887 and 1894, the first successful short cinematographic presentations were established. The biggest popular breakthrough of the technology came in 1895 with the first projected movies that lasted longer than 10 seconds. During the first years after this breakthrough, most motion pictures lasted about 50 seconds, lacked synchronized sound and natural colour, and were mainly exhibited as novelty attractions. In the first decades of the 20th century, movies grew much longer and the medium quickly developed into one of the most important tools of communication and entertainment. The breakthrough of synchronized sound occurred at the end of the 1920s and that of full color motion picture film in the 1930s. By the start of the 21st century, physical film stock was being replaced with digital film technologies at both ends of the production chain by digital image sensors and projectors.
