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Head-coupled perspective

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Head-coupled perspective is a rendering technique in which a computer draws a 3D scene on a display that stays fixed in the world, such as a monitor, a phone screen or a projection wall, using a perspective projection computed from the viewer's tracked eye or head position. As the viewer moves, the image is redrawn so that the screen behaves like a window into a virtual space rather than a flat picture, which adds motion parallax to the other depth cues of the image.[1][2] Colin Ware, Kevin Arthur and Kellogg Booth named a monitor display that combines head-coupled perspective with stereoscopic images fish tank virtual reality (fish tank VR or FTVR) at CHI 1993; later researchers also apply the term to head-coupled displays that use either cue or both.[3][4][5]

The same off-axis projection underlies projection systems such as the CAVE, and the technique has reached consumers through head-tracked and eye-tracked displays including the Amazon Fire Phone, Sony's Spatial Reality Display and Google's Project Starline (later Google Beam).[6][7][8][9]

Reviewed 4 October 2026. Claims checked against the Arthur 1993 thesis, the CAVE, pCubee and Project Starline papers, Crossref and OpenAlex metadata and abstracts for every DOI citation, and every cited web page. About review dates.

How it works

Conventional 3D graphics treats the viewer as a single point placed at some distance straight out from the center of the screen, so the image is only geometrically correct from that one position. Arthur's 1993 thesis at the University of British Columbia defines head-coupled perspective as computing the displayed images "with perspective projections defined by the positions of the observer's eyes", and calls a monitor-based system that uses it a head-coupled display.[1] Because the eye is generally not centered in front of the screen, the projection is an off-axis (asymmetric) one: the viewing pyramid runs from the eye point to the four physical corners of the screen. A photograph sequence in the thesis shows a car model that looks undistorted and three-dimensional only when the camera position matches the eye point used for the projection.[1]

The designers of the CAVE described the same approach as a "window projection paradigm", in contrast to the "camera" paradigm used for head-mounted displays and the BOOM: the projection plane and the projection point relative to it are specified, which creates an off-axis perspective projection, and in the CAVE the projection planes are the physical walls, so the projection is recomputed for each eye from the viewer's position as the viewer moves.[6] Robert Kooima's 2008 write-up "Generalized Perspective Projection" explains why the standard OpenGL projection calls fail in virtual reality setups: gluPerspective assumes the user is directly in front of the screen, facing perpendicular to it and looking at its center, and glFrustum assumes a screen lying in a fixed plane. His method computes a correct projection from the measured screen corners and the tracked eye position, and he illustrates it with the 60-panel Varrier autostereoscopic wall at Calit2, where 120 distinct perspective projections are needed to render one consistent scene for a tracked user.[10]

The system needs to know where the eyes are. Systems typically track the head and estimate the eye positions relative to a reference point on the tracker, which is why the technique depends on head tracking or face tracking hardware.[1] Michael Deering of Sun Microsystems set out the requirements for accurate head-tracked stereo on a workstation CRT in his SIGGRAPH 1992 paper: predictive head tracking, dynamic optical location of the viewer's eye points, physically accurate stereo perspective viewing matrices, and corrections for the refraction and curvature of the CRT glass. His system achieved sub-centimeter registration between virtual and physical objects.[11] Arthur notes, citing Deering, that the effective viewpoint of the eye (its first nodal point) sits about 0.6 cm in front of the eye's center of rotation and so moves when the eye rotates; he judged the resulting error unlikely to be larger than errors from tracker inaccuracy and CRT distortion.[1]

Head coupling also removes an artifact of fixed-viewpoint stereo. When a viewer moves in front of a static stereo image, the scene appears to bend about the image plane and follow the viewer, an effect called induced stereo movement. Arthur writes that the effect disappears when the projection is correctly coupled to head position.[1]

Relation to head-mounted displays

McKenna's 1992 paper treats stereoscopic head-mounted displays as "a simplified, special case" of the same viewpoint-dependent rendering, because in a headset the eyes and screens move together. The class of displays that use the changing relative position of the eyes and a world-fixed or handheld screen as input was, in his words, "largely overlooked".[2] Arthur adds that headsets still need off-axis projections even though their screens are fixed relative to the eyes, since the screens are usually angled away from the face.[1]

Terminology

Researchers have used several names for monitor-based systems of this kind. Arthur lists fish tank virtual reality, viewpoint dependent imaging and virtual integral holography, and distinguishes head-coupled perspective (the projection technique) from head-coupled stereo display (head-coupled perspective plus stereoscopic images).[1] The University of New Hampshire's Data Visualization Research Lab credits Colin Ware with coining "Fish Tank VR" for a small virtual workspace that sits outside the user, as opposed to a helmet that cuts the user off from the real world.[5] Jun Rekimoto's 1995 paper uses "desk top virtual reality" as another name for fish tank VR,[12] and Johnny Chung Lee titled his 2007 demonstration "Head Tracking for Desktop VR Displays".[13]

History

Early systems

According to Arthur's survey of prior work, the earliest reported display of this type was Stereomatrix, described by W. J. Kubitz and W. J. Poppelbaum in 1973. The viewer looked at a 3 by 4 foot rear-projection screen lit by lasers, and photodetectors tracked an infrared source worn on the head. A 1982 system by Diamond and colleagues showed line-segment molecular models on a monitor with head-coupled perspective but without stereo, tracking a small light bulb on the user's forehead with a video camera.[1]

Scott Fisher described a "viewpoint dependent imaging" system in a paper published in SPIE proceedings volume 367. It produced an interactive, life-size stereoscopic image that "becomes a window into a three dimensional visual environment", updated continuously as the user moved relative to the display surface. Instead of rendering in real time, it retrieved the changing viewpoints from a stereoscopic image array stored on a computer-controlled optical videodisc, synchronized to the viewer's movements as detected by a body-tracking device. Fisher aimed to present binocular parallax, motion parallax and motion perspective, cues that traditional media did not offer.[14] Arthur notes that most early systems were limited to wireframe images because shaded rendering was too expensive, and that precomputed images, as Fisher suggested, were one way around this.[1]

1992 to 1995: workstation fish tanks

By the early 1990s commercial trackers and graphics workstations made the technique practical, and research turned from implementation to evaluation.[1] McKenna built three prototypes in 1992: a fixed high-resolution monitor with head-corrected perspective, the same monitor with its own tilt and swivel tracked, and a freely moving handheld LCD. A simple experiment indicated that tracking the head improved the ability to pick specific 3D locations on a 2D display, compared with a fixed view and a mouse-controlled view.[2] Deering's 1992 paper described the Sun system above, and Arthur records that Deering also built the Virtual Portal, which showed head-coupled stereo images on three large projection screens.[11][1] The 1993 CAVE paper cites the Virtual Portal, a closet-sized three-wall projection system demonstrated by Sun, as related work.[6]

Ware, Arthur and Booth defined fish tank virtual reality at CHI 1993 as "a stereo image of a three dimensional (3D) scene viewed on a monitor using a perspective projection coupled to the head position of the observer".[3] Their experimental system ran on a Silicon Graphics Iris 4D 240/VGX workstation. Subjects wore StereoGraphics CrystalEyes shutter glasses synchronized to a monitor refreshing at 120 Hz (60 Hz per eye), and a Shooting Star Technology ADL-1 mechanical head tracker, mounted on a wooden frame about 40 cm above the monitor, measured head position. The eyes were about 50 cm from the screen, and the manufacturer rated the ADL-1's lag at less than 3 ms.[1] The results are summarized in the research section below.

In 1995 Jun Rekimoto presented a vision-based head tracker for fish tank VR that needed no head gear. It combined two simple image processing techniques in software on a mid-range workstation to report the head position in real time, and an experiment suggested it could improve the user's understanding of complex 3D structures on the display.[12]

Wii Remote demonstration

On 21 December 2007, Johnny Chung Lee published "Head Tracking for Desktop VR Displays using the Wiimote". He reversed the Nintendo Wii's usual arrangement: the Wii Remote's infrared camera sat near the screen and watched a head-mounted "sensor bar" of two infrared LEDs, so the software could "accurately track the location of your head and render view dependent images on the screen".[13][15] In a follow-up FAQ he wrote that "when just doing head tracking, the conflicting stereo depth cues weakens the illusion", suggested shutter or polarized glasses to give each eye its own image, and noted that the Wii Remote's camera field of view was only 45 degrees.[16]

Research

Head coupling versus stereo

The 1993 UBC experiments compared five viewing conditions. In a paired-comparison test with seven subjects, head coupling without stereo was preferred over stereo alone in 91% of comparisons (averaging the monocular and binocular head-coupled conditions).[1] In a second experiment ten subjects traced a leaf to its root through two intermeshed 3D trees, a task adapted from Sollenberger and Milgram's work on tracing arterial branching in brain scans:[1]

Tree-tracing results, Experiment 2 (Arthur 1993)
Viewing condition Mean response time (s) Errors (%)
Picture (no stereo, no head coupling) 7.50 21.8
Stereo only 8.09 14.7
Head-coupled, monocular 8.66 3.7
Head-coupled, binocular (same image to both eyes) 9.12 2.7
Head-coupled with stereo 6.83 1.3

The CHI paper summarized the error rates as 22% for the pictorial display, 14.7% for stereo alone, 3.2% for head coupling alone and 1.3% for head-coupled stereo, and concluded that "head coupling is probably more important than stereo in 3D visualization and that head coupling and stereo combined provide an important enhancement to monitor based computer graphics".[3][1]

Later work found that the answer depends on the task. Roland Arsenault and Colin Ware used a Fitts' law tapping task in a fish tank VR setup and found that stereo was "considerably more important than eye-coupled perspective" for visually guided hand movement: disabling stereo increased mean intertap intervals by 33%, while disabling head tracking increased them by 11%.[17] For spherical displays, Dylan Fafard and colleagues at UBC and the University of Saskatchewan simulated a spherical FTVR display inside a VR headset so they could control calibration error and tracking latency. Almost all spherical FTVR systems had omitted stereo; the study found that without it, median task time rose by 20% to 91%, and recommended that spherical FTVR displays include stereo.[18]

Lag and frame rate

Arthur's third experiment simulated tracker lag and reduced frame rates (30, 15 and 10 Hz) under full head-coupled stereo. Response times rose sharply as total lag increased, with serious degradation even at about 200 ms, and the results suggested that frame rate matters less than tracker latency.[1] In a 1994 study of reaching in a head-coupled stereo display with hand tracking, Ware and Ravin Balakrishnan found that lag in the head-tracking system was relatively unimportant for performance while lag in the hand-tracking system was critical, and they modeled the effect of hand lag as a multiplicative term on the Fitts' law index of difficulty.[19]

Perception on the screen surface

Because the viewer of an FTVR display is still looking at pixels on a 2D surface, a 2020 CHI study by Qian Zhou, Fan Wu, Sidney Fels and Ian Stavness examined whether the on-screen size of an object affects its perceived 3D size on a spherical display. On-screen size had a significant influence, causing 83.3% under- or overestimation of size without stereopsis and 64.7% with it, and objects looked smaller as the viewer moved closer, the opposite of real-world experience.[20]

Implementations

Research displays

Head-coupled perspective extends to several screens at once when each screen gets its own projection from the shared eye position. The CAVE computes off-axis stereo projections for each wall from the tracked viewer.[6] pCubee (CHI 2010), by Ian Stavness, Billy Lam and Sidney Fels, arranged five small LCD panels into a handheld box and corrected the perspective of each screen to the user's head position, tracked with a Polhemus Fastrak sensor in a pair of headphones, so that virtual objects appeared to sit inside the box. It rendered monocular rather than stereo views because of synchronization limits of its LCD panels.[4] The same groups later built a spherical display that gives two people their own unobstructed 3D perspective views while they can still see and talk to each other, and evaluated it at a four-day exhibition.[21] A UBC announcement describes the display, named Crystal, as a 24-inch (600 mm) hollow sphere lit by four high-speed projectors, with one camera used for calibration.[22]

Commercial products

Product Maker Date How the viewer is tracked
zSpace Infinite Z Reported December 2012 Infrared markers in the companion glasses[23]
Fire Phone (Dynamic Perspective) Amazon Announced 18 June 2014 Four front cameras and four infrared LEDs[7]
Spatial Reality Display ELF-SR1 Sony Announced 15 October 2020 Built-in high-speed eye-sensing camera[8][24]
Project Starline, renamed Google Beam Google; Beam hardware by HP Paper December 2021; Beam May 2025 Four 1280x1024 monochrome cameras at 120 Hz in the Starline research system[9]

New Atlas reported in 2012 that Infinite Z's zSpace display tracked infrared markers in its glasses and adjusted the 3D image in real time to produce motion parallax, which ordinary stereo displays lack; it also tracked a stylus for manipulating virtual objects.[23]

Amazon announced the Fire Phone on 18 June 2014, with shipping set for 25 July 2014. Its Dynamic Perspective feature combined four ultra-low-power cameras and four infrared LEDs on the front face, a dedicated processor, computer vision algorithms and a rendering engine to recognize "where a user's head is relative to the device".[7] TechCrunch reported that the cameras sat in the four corners with 120-degree fields of view, that two were active at any time, and that the interface used the effect for parallax-like layering and 60 fps 3D effects.[25] Amazon sold its remaining stock at the end of August 2015, and Engadget wrote that the "centerpiece Dynamic Perspective feature" had been "widely considered a novelty".[26]

Sony announced the 15.6-inch Spatial Reality Display on 15 October 2020 at a suggested retail price of US$4,999.99, available to order in November 2020. Sony states that it tracks the viewer's eye position on the vertical, horizontal and depth axes and renders the image in real time based on that position.[8] Sony's developer white paper says a camera in the bezel supplies face-tracking and eye-sensing data, the runtime software has supported game engines "pivot the scene according to your head motions", and a micro optical lens in front of the LCD directs a separate image to each eye.[24]

Google's Project Starline research system, described in ACM Transactions on Graphics in 2021, used a head-tracked autostereoscopic display built on a 65-inch 8K panel at 60 Hz. The tracked eye locations set the stereo viewpoints for rendering and steered the left and right views to the matching eyes. The team measured a tracking latency of about 33 ms and compensated by extrapolating the tracked positions with double exponential smoothing, since lag in the eye points causes crosstalk and, if large, stereo reversal. The authors chose a screen-based design partly because of the weight and discomfort of most AR and VR headsets, noting that widely available VR headsets had an angular resolution below 20 pixels per degree, against about 45 pixels per degree for their display at the nominal 1.25 m viewing distance.[9] Google renamed the project Google Beam at I/O in May 2025, citing millimeter-level head tracking and 60 fps video streaming.[27] The first Beam device, the HP Dimension with Google Beam, was announced in June 2025 at US$24,999 for select enterprise customers in the US, Canada, the UK, France, Germany and Japan, with availability planned for late 2025.[28] In September 2026 Google said it was shipping Beam units to customers in those six countries.[29]

Applications in VR and AR

Head-coupled perspective gives screen-based systems the viewpoint-dependent rendering that headsets get from head tracking, without a display worn over the eyes. The CAVE authors made it part of their definition of virtual reality, which they confined to "real-time viewer-centered head-tracking perspective with a large angle of view, interactive control, and binocular display".[6] Arthur argued in 1993 that many applications, such as medical visualization, do not need immersion, and that a monitor-based fish tank keeps the user connected to the keyboard, the work environment and colleagues.[1] Starline's designers made a similar argument for telepresence, choosing a head-tracked display over a headset to avoid headset weight and the difficulty of capturing a face through one.[9] Head-coupled rendering is also used in VR research itself: Fafard and colleagues ran their spherical-display study as a simulation inside a headset.[18]

Limitations

The projection is correct only for the tracked eye positions, so other people watching the same screen see a distorted image. Lee wrote that the Wii Remote's 45-degree camera field of view "might be cramped with 2 people",[16] and the UBC and Saskatchewan group built its two-person spherical display because almost all FTVR systems had been single-person experiences.[21]

Tracker lag degrades task performance, and in autostereoscopic systems lag in the tracked eye positions also causes crosstalk between the left and right views.[1][9] Depth cues can conflict as well. Without stereo, the flat image contradicts the depth implied by motion parallax, which Lee said weakens the illusion.[16] With stereo, the eyes converge on virtual objects but must focus on the screen surface, the vergence-accommodation conflict. Arthur noted that the problem shrinks when virtual objects are close to the screen, and the Starline team placed the remote user's face near the display plane for the same reason.[1][9]

Accurate results also depend on calibration: the physical positions of the screen corners, correction for tracker distortion, and per-user values such as eye spacing and the position of the eyes relative to the tracker.[1][10]

See also

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 1.17 1.18 1.19 1.20 Kevin Wayne Arthur (1993-07). "3D Task Performance Using Head-Coupled Stereo Displays". M.Sc. thesis, Department of Computer Science, University of British Columbia. https://www.cs.ubc.ca/labs/imager/th/1993/Arthur1993/Arthur1993.pdf. Retrieved 2026-10-04.
  2. ↑ 2.0 2.1 2.2 Michael McKenna (1992). "Interactive viewpoint control and three-dimensional operations". Proceedings of the 1992 Symposium on Interactive 3D Graphics (SI3D '92), pp. 53-56. ACM. https://doi.org/10.1145/147156.147163. Retrieved 2026-10-04.
  3. ↑ 3.0 3.1 3.2 Colin Ware, Kevin Arthur, Kellogg S. Booth (1993). "Fish tank virtual reality". Proceedings of the INTERACT '93 and CHI '93 Conference on Human Factors in Computing Systems, pp. 37-42. ACM. https://doi.org/10.1145/169059.169066. Retrieved 2026-10-04.
  4. ↑ 4.0 4.1 Ian Stavness, Billy Lam, Sidney Fels (2010-04). "pCubee: A Perspective-Corrected Handheld Cubic Display". Proceedings of the SIGCHI Conference on Human Factors in Computing Systems (CHI 2010), pp. 1381-1390. ACM. https://www.cs.usask.ca/faculty/stavness/papers/stavness2010-pcubee.pdf. Retrieved 2026-10-04.
  5. ↑ 5.0 5.1 "Fishtank VR". Data Visualization Research Lab, Center for Coastal and Ocean Mapping, University of New Hampshire. https://vislab-ccom.unh.edu/projects/fishtank_vr/. Retrieved 2026-10-04.
  6. ↑ 6.0 6.1 6.2 6.3 6.4 Carolina Cruz-Neira, Daniel J. Sandin, Thomas A. DeFanti (1993). "Surround-Screen Projection-Based Virtual Reality: The Design and Implementation of the CAVE". Proceedings of SIGGRAPH '93, pp. 135-142. ACM. https://www.evl.uic.edu/documents/siggraph93-cave-cruz-neira.pdf. Retrieved 2026-10-04.
  7. ↑ 7.0 7.1 7.2 "Introducing Fire, the First Smartphone Designed by Amazon". Amazon Press Center. Amazon. 2014-06-18. https://press.aboutamazon.com/2014/6/introducing-fire-the-first-smartphone-designed-by-amazon. Retrieved 2026-10-04.
  8. ↑ 8.0 8.1 8.2 "Sony Electronics Launches Groundbreaking Spatial Reality Display, Bringing Creators' Designs to Life". PR Newswire. Sony Electronics. 2020-10-15. https://www.prnewswire.com/news-releases/sony-electronics-launches-groundbreaking-spatial-reality-display-bringing-creators-designs-to-life-301153750.html. Retrieved 2026-10-04.
  9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 Jason Lawrence, Dan B Goldman, Supreeth Achar, Gregory Major Blascovich, Joseph G. Desloge, Tommy Fortes, Eric M. Gomez, Sascha Häberling, Hugues Hoppe, Andy Huibers, Claude Knaus, Brian Kuschak, Ricardo Martin-Brualla, Harris Nover, Andrew Ian Russell, Steven M. Seitz, Kevin Tong (2021-12). "Project Starline: A high-fidelity telepresence system". ACM Transactions on Graphics, vol. 40, no. 6, article 242. https://doi.org/10.1145/3478513.3480490. Retrieved 2026-10-04.
  10. ↑ 10.0 10.1 Robert Kooima (2008). "Generalized Perspective Projection". Louisiana State University (archived). http://web.archive.org/web/20190920230956/http://csc.lsu.edu/~kooima/articles/genperspective/. Retrieved 2026-10-04.
  11. ↑ 11.0 11.1 Michael Deering (1992-07). "High resolution virtual reality". Proceedings of SIGGRAPH '92 (Computer Graphics, vol. 26, no. 2), pp. 195-202. ACM. https://doi.org/10.1145/133994.134039. Retrieved 2026-10-04.
  12. ↑ 12.0 12.1 Jun Rekimoto (1995). "A vision-based head tracker for fish tank virtual reality: VR without head gear". Proceedings of the Virtual Reality Annual International Symposium (VRAIS '95), pp. 94-100. IEEE. https://doi.org/10.1109/VRAIS.1995.512484. Retrieved 2026-10-04.
  13. ↑ 13.0 13.1 Johnny Chung Lee (2007-12-21). "Head Tracking for Desktop VR Displays using the Wiimote". Procrastineering. http://procrastineering.blogspot.com/2007/12/head-tracking-for-desktop-vr-displays.html. Retrieved 2026-10-04.
  14. ↑ Scott S. Fisher (1983). "Viewpoint Dependent Imaging: An Interactive Stereoscopic Display". Processing and Display of Three-Dimensional Data, Proc. SPIE vol. 367, pp. 41-45. SPIE. https://doi.org/10.1117/12.934299. Retrieved 2026-10-04.
  15. ↑ Donald Melanson (2007-12-21). "DIY head-tracker takes Wiimote hacking to dizzying new heights". Engadget. https://www.engadget.com/2007-12-21-diy-head-tracker-takes-wiimote-hacking-to-dizzying-new-heights.html. Retrieved 2026-10-04.
  16. ↑ 16.0 16.1 16.2 Johnny Chung Lee (2007-12-21). "Wiimote DesktopVR - FAQ and Adv Discussion". Procrastineering. http://procrastineering.blogspot.com/2007/12/. Retrieved 2026-10-04.
  17. ↑ Roland Arsenault, Colin Ware (2004-10). "The Importance of Stereo and Eye-Coupled Perspective for Eye-Hand Coordination in Fish Tank VR". Presence: Teleoperators and Virtual Environments, vol. 13, no. 5, pp. 549-559. MIT Press. https://doi.org/10.1162/1054746042545300. Retrieved 2026-10-04.
  18. ↑ 18.0 18.1 Dylan Fafard, Ian Stavness, Martin Dechant, Regan Mandryk, Qian Zhou, Sidney Fels (2019-05). "FTVR in VR: Evaluation of 3D Perception With a Simulated Volumetric Fish-Tank Virtual Reality Display". Proceedings of the 2019 CHI Conference on Human Factors in Computing Systems, pp. 1-12. ACM. https://doi.org/10.1145/3290605.3300763. Retrieved 2026-10-04.
  19. ↑ Colin Ware, Ravin Balakrishnan (1994-12). "Reaching for objects in VR displays: lag and frame rate". ACM Transactions on Computer-Human Interaction, vol. 1, no. 4, pp. 331-356. https://doi.org/10.1145/198425.198426. Retrieved 2026-10-04.
  20. ↑ Qian Zhou, Fan Wu, Sidney Fels, Ian Stavness (2020-04). "Closer Object Looks Smaller: Investigating the Duality of Size Perception in a Spherical Fish Tank VR Display". Proceedings of the 2020 CHI Conference on Human Factors in Computing Systems, pp. 1-9. ACM. https://doi.org/10.1145/3313831.3376601. Retrieved 2026-10-04.
  21. ↑ 21.0 21.1 Dylan Brodie Fafard, Qian Zhou, Chris Chamberlain, Georg Hagemann, Sidney Fels, Ian Stavness (2018-11). "Design and implementation of a multi-person fish-tank virtual reality display". Proceedings of the 24th ACM Symposium on Virtual Reality Software and Technology (VRST '18), pp. 1-9. ACM. https://doi.org/10.1145/3281505.3281540. Retrieved 2026-10-04.
  22. ↑ "Spherical display brings virtual collaboration closer to reality". ScienceDaily. University of British Columbia. 2019-02-19. https://www.sciencedaily.com/releases/2019/02/190219080745.htm. Retrieved 2026-10-04.
  23. ↑ 23.0 23.1 Dario Borghino (2012-12-29). "zSpace display simulates motion parallax for more immersive 3D". New Atlas. https://newatlas.com/zspace-3d-display/25586/. Retrieved 2026-10-04.
  24. ↑ 24.0 24.1 "White Paper (ELF-SR1 only)". Sony XYN Developer Portal. Sony. https://xyn.sony.net/en/developer/technical/spatial-reality-display/whitepaper. Retrieved 2026-10-04.
  25. ↑ Jordan Crook (2014-06-18). "Amazon's Fire Phone Uses Depth And 3D Effects To Stand Out". TechCrunch. https://techcrunch.com/2014/06/18/amazons-fire-phone-uses-depth-and-3d-effects-to-stand-out/. Retrieved 2026-10-04.
  26. ↑ Jon Fingas (2015-09-09). "Amazon stops selling the Fire Phone". Engadget. https://www.engadget.com/2015-09-09-amazon-stops-fire-phone-sales.html. Retrieved 2026-10-04.
  27. ↑ Kyle Wiggers (2025-05-20). "Google's 3D teleconferencing platform, now called Beam, will ship later in 2025". TechCrunch. https://techcrunch.com/2025/05/20/googles-3d-teleconferencing-platform-now-called-beam-will-ship-later-in-2025. Retrieved 2026-10-04.
  28. ↑ Abner Li (2025-06-11). "The first Google Beam device is the $24,999 HP Dimension". 9to5Google. https://9to5google.com/2025/06/11/hp-dimension-with-google-beam/. Retrieved 2026-10-04.
  29. ↑ Abner Li (2026-09-23). "Google Beam 3D meeting booths coming to co-working spaces". 9to5Google. https://9to5google.com/2026/09/23/google-beam-co-working/. Retrieved 2026-10-04.
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