3D display
A 3D display is a
As of 2021, the most common type of 3D display is a stereoscopic display, which is the type of display used in almost all virtual reality equipment. 3D displays can be near-eye displays like in VR headsets, or they can be in a device further away from the eyes like a 3D-enabled mobile device or 3D movie theater.
The term “3D display” can also be used to refer to a volumetric display which may generate content that can be viewed from all angles.
History
The first 3D display was created by
Stereoscopic displays
Stereoscopic displays are commonly referred to as “stereo displays,” “stereo 3D displays,” “stereoscopic 3D displays,” or sometimes erroneously as just “3D displays.”
The basic technique of stereoscopic 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, the presentation of dual 2D images is distinctly different from displaying a light field, and is also different from displaying an image in three-dimensional space.
The most notable difference to displays that can show full 3D is that the observer's head movements and change in
It is 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. 3D displays are often referred to as also stereoscopic displays because they meet the lower criteria of being stereoscopic as well.
Based on the principles of
Side-by-side images
Traditional stereoscopic photography consists of creating a 3D illusion starting from a pair of 2D images, a
If eyestrain and distortion are to be avoided, each of the two 2D images preferably should be presented to each eye of the viewer so that any object at infinite distance seen by the viewer should be perceived by that eye while it is oriented straight ahead, the viewer's eyes being neither crossed nor diverging. When the picture contains no object at infinite distance, such as a horizon or a cloud, the pictures should be spaced correspondingly closer together.
The side-by-side method is extremely simple to create, but it can be difficult or uncomfortable to view without optical aids.
Stereoscope and stereographic cards
A stereoscope is a device for viewing stereographic cards, which are cards that contain two separate images that are printed side by side to create the illusion of a three-dimensional image.
Transparency viewers
Pairs of stereo views printed on a transparent base are viewed by transmitted light. One advantage of transparency viewing is the opportunity for a wider, more realistic dynamic range than is practical with prints on an opaque base; another is that a wider field of view may be presented since the images, being illuminated from the rear, may be placed much closer to the lenses.
The practice of viewing film-based stereoscopic transparencies dates to at least as early as 1931, when
Head-mounted displays
The user typically wears a helmet or glasses with two small
Owing to rapid advancements in computer graphics and the continuing miniaturization of video and other equipment these devices are beginning to become available at more reasonable cost. Head-mounted or wearable glasses may be used to view a see-through image imposed upon the real world view, creating what is called augmented reality. This is done by reflecting the video images through partially reflective mirrors. The real world can be seen through the partial mirror.
A recent development in holographic-waveguide or "waveguide-based optics" allows a stereoscopic images to be superimposed on real world without the uses of bulky reflective mirror.[2][3]
Head-mounted projection displays
Head-mounted projection displays (HMPD) is similar to head-mounted displays but with images projected to and displayed on a
3D glasses
Active shutter systems
With the eclipse method, a shutter blocks light from each appropriate eye when the converse eye's image is projected on the screen. The display alternates between left and right images, and opens and closes the shutters in the glasses or viewer in synchronization with the images on the screen. This was the basis of the Teleview system which was used briefly in 1922.[6][7]
A variation on the eclipse method is used in
Liquid crystal light valves work by rotating light between two polarizing filters. Due to these internal polarizers, LCD shutter-glasses darken the display image of any LCD, plasma, or projector image source, which has the result that images appear dimmer and contrast is lower than for normal non-3D viewing. This is not necessarily a usage problem; for some types of displays which are already very bright with poor grayish black levels, LCD shutter glasses may actually improve the image quality.
Anaglyph
In an anaglyph, the two images are
An alternative to the usual red and cyan filter system of anaglyph is ColorCode 3-D, a patented anaglyph system which was invented in order to present an anaglyph image in conjunction with the NTSC television standard, in which the red channel is often compromised. ColorCode uses the complementary colors of yellow and dark blue on-screen, and the colors of the glasses' lenses are amber and dark blue.
Polarization systems
To present a stereoscopic picture, two images are projected superimposed onto the same screen through different
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.
Polarized light reflected from an ordinary motion picture screen typically loses most of its polarization. So an expensive silver screen or aluminized screen with negligible polarization loss has to be used. 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.
Interference filter technology
Dolby 3D uses specific wavelengths of red, green, and blue for the right eye, and different wavelengths of red, green, and blue for the left eye. Eyeglasses which filter out the very specific wavelengths allow the wearer to see a 3D image. This technology eliminates the expensive silver screens required for polarized systems such as RealD, which is the most common 3D display system in theaters. It does, however, require much more expensive glasses than the polarized systems. It is also known as spectral comb filtering or wavelength multiplex visualization
The Omega 3D/
Other
The
Prismatic glasses make cross-viewing easier as well as over/under-viewing possible, examples include the KMQ viewer.
Autostereoscopy
In this method, glasses are not necessary to see the stereoscopic image. Lenticular lens and parallax barrier technologies involve imposing two (or more) images on the same sheet, in narrow, alternating strips, and using a screen that either blocks one of the two images' strips (in the case of parallax barriers) or uses equally narrow lenses to bend the strips of image and make it appear to fill the entire image (in the case of lenticular prints). To produce the stereoscopic effect, the person must be positioned so that one eye sees one of the two images and the other sees the other. The optical principles of multiview auto-stereoscopy have been known for over a century.[11]
Both images are projected onto a high-gain, corrugated screen which reflects light at acute angles. In order to see the stereoscopic image, the viewer must sit within a very narrow angle that is nearly perpendicular to the screen, limiting the size of the audience. Lenticular was used for theatrical presentation of numerous shorts in Russia from 1940 to 1948
Though its use in theatrical presentations has been rather limited, lenticular has been widely used for a variety of novelty items and has even been used in amateur 3D photography.
Volumetric display
Volumetric displays use some physical mechanism to display points of light within a volume. Such displays use voxels instead of pixels. Volumetric displays include multiplanar displays, which have multiple display planes stacked up, and rotating panel displays, where a rotating panel sweeps out a volume.
Other technologies have been developed to project light dots in the air above a device. An infrared laser is focused on the destination in space, generating a small bubble of plasma which emits visible light.
Light field / holographic display
A light field display tries to recreate a "light field" on the surface of the display. In contrast to a 2D display which shows a distinct color on each pixel, a light field display shows a distinct color on each pixel for each direction that the light ray emits to. This way, eyes from different positions will see different pictures on the display, creating parallax and thus creating a sense of 3D. A light field display is like a glass window, people see 3D objects behind the glass, despite that all light rays they see come from (through) the glass.
The light field in front of the display can be created in two ways: 1) by emitting different light rays in different directions at each point on the display; 2) by recreating a
Holographic displays
Holographic display is a
In 2013, a Silicon valley Company
Integral imaging
Integral imaging is an autostereoscopic or multiscopic 3D display, meaning that it displays a 3D image without the use of special glasses on the part of the viewer. It achieves this by placing an array of microlenses (similar to a lenticular lens) in front of the image, where each lens looks different depending on viewing angle. Thus rather than displaying a 2D image that looks the same from every direction, it reproduces a 3D light field, creating stereo images that exhibit parallax when the viewer moves.
Compressive light field displays
A new display technology called "compressive light field" is being developed. These prototype displays use layered LCD panels and compression algorithms at the time of display. Designs include dual[18] and multilayer[19][20][21] devices that are driven by algorithms such as
Problems
Each of these display technologies can be seen to have limitations, whether the location of the viewer, cumbersome or unsightly equipment or great cost. The display of artifact-free 3D images remains difficult.[citation needed]
See also
References
- ^ Holliman, Nicolas S.; Dodgson, Neil A.; Favalora, Gregg E.; Pockett, Lachlan (June 2011). "Three-Dimensional Displays: A Review and Applications Analysis" (PDF). IEEE Transactions on Broadcasting. 57 (2).
- ^ "New holographic waveguide augments reality". IOP Physic World. 2014.
- ^ "Holographic Near-Eye Displays for Virtual and Augmented Reality". Microsoft Research. 2017.
- PMID 19550732.
- PMID 25089403.
- ^ Amazing 3D by Hal Morgan and Dan Symmes Little, Broawn & Company (Canada) Limited, pp. 15–16.
- ^ ""The Chopper", article by Daniel L. Symmes". 3dmovingpictures.com. Retrieved 2010-10-14.
- ^ "Samsung 3D". www.berezin.com. Retrieved 2017-12-02.
- ^ Make Your own Stereo Pictures Julius B. Kaiser The Macmillan Company 1955 page 271 Archived 2011-02-26 at the Wayback Machine
- ^ "Seeing is believing""; Cinema Technology, Vol 24, No.1 March 2011
- ^ Okoshi, Three-Dimensional Imaging Techniques, Academic Press, 1976
- ^ Amazing 3D by Hal Morgan and Dan Symmes Little, Broawn & Company (Canada) Limited, pp. 104–105
- ^ "The ASC: Ray Zone and the "Tyranny of Flatness" « John Bailey's Bailiwick". May 18, 2012.
- ^ Make Your own Stereo Pictures Julius B. Kaiser The Macmillan Company 1955 pp. 12–13.
- ^ Son of Nimslo, John Dennis, Stereo World May/June 1989 pp. 34–36.
- ^ a b Masahiro Yamaguchi; Koki Wakunami. "Ray-based and Wavefront-based 3D Representations for Holographic Displays" (PDF).
- S2CID 4424212.
- ^ Lanman, D.; Hirsch, M.; Kim, Y.; Raskar, R. (2010). "Content-adaptive parallax barriers: optimizing dual-layer 3D displays using low-rank light field factorization".
- ^ Wetzstein, G.; Lanman, D.; Heidrich, W.; Raskar, R. (2011). "Layered 3D: Tomographic Image Synthesis for Attenuation-based Light Field and High Dynamic Range Displays". ACM Transactions on Graphics (SIGGRAPH).
- ^ Lanman, D.; Wetzstein, G.; Hirsch, M.; Heidrich, W.; Raskar, R. (2019). "Polarization Fields: Dynamic Light Field Display using Multi-Layer LCDs". ACM Transactions on Graphics (SIGGRAPH Asia).
- ^ Wetzstein, G.; Lanman, D.; Hirsch, M.; Raskar, R. (2012). "Tensor Displays: Compressive Light Field Synthesis using Multilayer Displays with Directional Backlighting". ACM Transactions on Graphics (SIGGRAPH).