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Vergence-accommodation conflict (edit)
Revision as of 12:58, 20 September 2024
, 12:58, 20 September 2024no edit summary
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Meta Half Dome prototypes addressed the problem with variable focus lenses that matched focal depth to vergence stereoscopic depth.<ref>{{Cite web |last=VR |first=Oculus |title=Introducing the Team Behind Half Dome—Facebook Reality Labs' Varifocal Prototype {{!}} Meta Quest Blog |url=https://www.oculus.com/blog/introducing-the-team-behind-half-dome-facebook-reality-labs-varifocal-prototype/ |access-date=2023-06-13 |website=www.oculus.com |language=en}}</ref> The first prototype used bulky mechanical actuators to refocus the lens. The third prototype used a stack of 6 liquid crystal lens layers where each layer could be turned on and off by applying a voltage, and this creates 64 discrete focal planes.<ref>{{Cite web |date=2020-07-28 |title=Facebook's Display Research Lead: Varifocal Half-Dome 3 'Almost Ready For Prime Time' |url=https://www.uploadvr.com/half-dome-3-prime-time/ |access-date=2023-06-13 |website=UploadVR |language=en}}</ref> There are currently no production products using this technology.
Most people can tolerate some extent of vergence-focal conflict, without noticeable onset of adverse effects. While it depends on a particular person and viewing distance, vergence-focal conflict of around up to 0.4 Diopters is within comfort limits of most people.<ref name="Shibata 11–11"/>
Most people can tolerate some extent of vergence-focal conflict, without noticeable onset of adverse effects. While it depends on a particular person and viewing distance, vergence-focal conflict of around up to 0.4 Diopters is within comfort limits of most people.<ref name="Shibata 11–11"/>
−==Causes==
==Causes==
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Varifocal displays are a concept explored mainly in VR display solutions. The basic principle relies on dynamically adjusting focal distance of displays based on the gaze direction. The technique requires an eye-tracking solution and means of modulating focal distance of a screen. Modulation of a focal distance can be, for example, [https://www.youtube.com/watch?v=JdM5SnSnuyQ&t=4s physical actuation of the screen] in relation to a fixed eyepiece optics, alternatively it can be utilization of varifocal<ref>{{Cite journal |doi=10.1364/OE.27.015627 |title=Design and demonstration of a vari-focal optical see-through head-mounted display using freeform Alvarez lenses |year=2019 |last1=Wilson |first1=Austin |last2=Hua |first2=Hong |journal=Optics Express |volume=27 |issue=11 |pages=15627–15637 |pmid=31163757 |bibcode=2019OExpr..2715627W |s2cid=174815078 |hdl=10150/633572 |hdl-access=free }}</ref><ref>{{Cite book |last1=Stevens |first1=R. E. |last2=Rhodes |first2=D. P. |last3=Hasnain |first3=A. |last4=Laffont |first4=P.-Y. |title=Digital Optics for Immersive Displays |chapter=Varifocal technologies providing prescription and VAC mitigation in HMDS using Alvarez lenses |editor-first1=Bernard C |editor-first2=Hagen |editor-first3=Wolfgang |editor-last1=Kress |editor-last2=Stolle |editor-last3=Osten |date=2018-05-21 |chapter-url=https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10676/106760J/Varifocal-technologies-providing-prescription-and-VAC-mitigation-in-HMDs-using/10.1117/12.2318397.full |publisher=SPIE |volume=10676 |pages=142–158 |doi=10.1117/12.2318397|bibcode=2018SPIE10676E..0JS |isbn=9781510618787 |s2cid=173178593 }}</ref> lens element(s). While varifocal approach mitigates or entirely solves VAC, it cannot convey realistic monocular focus cues. To try to add realism, these techniques rely on [https://www.cl.cam.ac.uk/~rkm38/pdfs/march2022_impact_of_focus_cues.pdf image processing techniques to simulate focus cues].
Varifocal displays are a concept explored mainly in VR display solutions. The basic principle relies on dynamically adjusting focal distance of displays based on the gaze direction. The technique requires an eye-tracking solution and means of modulating focal distance of a screen. Modulation of a focal distance can be, for example, [https://www.youtube.com/watch?v=JdM5SnSnuyQ&t=4s physical actuation of the screen] in relation to a fixed eyepiece optics, alternatively it can be utilization of varifocal<ref>{{Cite journal |doi=10.1364/OE.27.015627 |title=Design and demonstration of a vari-focal optical see-through head-mounted display using freeform Alvarez lenses |year=2019 |last1=Wilson |first1=Austin |last2=Hua |first2=Hong |journal=Optics Express |volume=27 |issue=11 |pages=15627–15637 |pmid=31163757 |bibcode=2019OExpr..2715627W |s2cid=174815078 |hdl=10150/633572 |hdl-access=free }}</ref><ref>{{Cite book |last1=Stevens |first1=R. E. |last2=Rhodes |first2=D. P. |last3=Hasnain |first3=A. |last4=Laffont |first4=P.-Y. |title=Digital Optics for Immersive Displays |chapter=Varifocal technologies providing prescription and VAC mitigation in HMDS using Alvarez lenses |editor-first1=Bernard C |editor-first2=Hagen |editor-first3=Wolfgang |editor-last1=Kress |editor-last2=Stolle |editor-last3=Osten |date=2018-05-21 |chapter-url=https://www.spiedigitallibrary.org/conference-proceedings-of-spie/10676/106760J/Varifocal-technologies-providing-prescription-and-VAC-mitigation-in-HMDs-using/10.1117/12.2318397.full |publisher=SPIE |volume=10676 |pages=142–158 |doi=10.1117/12.2318397|bibcode=2018SPIE10676E..0JS |isbn=9781510618787 |s2cid=173178593 }}</ref> lens element(s). While varifocal approach mitigates or entirely solves VAC, it cannot convey realistic monocular focus cues. To try to add realism, these techniques rely on [https://www.cl.cam.ac.uk/~rkm38/pdfs/march2022_impact_of_focus_cues.pdf image processing techniques to simulate focus cues].
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+Meta Half Dome prototypes addressed the problem with variable focus lenses that matched focal depth to vergence stereoscopic depth.<ref>{{Cite web |last=VR |first=Oculus |title=Introducing the Team Behind Half Dome—Facebook Reality Labs' Varifocal Prototype {{!}} Meta Quest Blog |url=https://www.oculus.com/blog/introducing-the-team-behind-half-dome-facebook-reality-labs-varifocal-prototype/ |access-date=2023-06-13 |website=www.oculus.com |language=en}}</ref> The first prototype used bulky mechanical actuators to refocus the lens. The third prototype used a stack of 6 liquid crystal lens layers where each layer could be turned on and off by applying a voltage, and this creates 64 discrete focal planes.<ref>{{Cite web |date=2020-07-28 |title=Facebook's Display Research Lead: Varifocal Half-Dome 3 'Almost Ready For Prime Time' |url=https://www.uploadvr.com/half-dome-3-prime-time/ |access-date=2023-06-13 |website=UploadVR |language=en}}</ref> There are currently no production products using this technology.
Multifocal displays are a way of overcoming focal conflict. The principle of operation relies on availability of multiple image focal planes (screens), which from the perspective of a viewer are available simultaneously at all times. This gives the ability to accommodate eyes within the available range of focal distances and perceive realistic monocular focus (image blur) cues similarly to natural viewing conditions. Essentially multifocal displays discretize the depth dimension and split or slice the 3D content according to the available configuration of depth planes to minimize focal conflict. The topic of multifocal displays has been generously researched for at least several [http://bankslab.berkeley.edu/publications/Files/stereo_display_prototype04.pdf decades],<ref>{{Cite journal |last1=MacKenzie |first1=Kevin J. |last2=Hoffman |first2=David M. |last3=Watt |first3=Simon J. |date=2010-07-01 |title=Accommodation to multiple‐focal‐plane displays: Implications for improving stereoscopic displays and for accommodation control |url=https://jov.arvojournals.org/article.aspx?articleid=2191682 |journal=Journal of Vision |language=en |volume=10 |issue=8 |pages=22 |doi=10.1167/10.8.22 |pmid=20884597 |issn=1534-7362|doi-access=free }}</ref><ref>{{Cite journal |doi=10.1364/AO.39.003209 |title=Multifocal planes head-mounted displays |year=2000 |last1=Rolland |first1=Jannick P. |last2=Krueger |first2=Myron W. |last3=Goon |first3=Alexei |journal=Applied Optics |volume=39 |issue=19 |pages=3209–3215 |pmid=18349886 |bibcode=2000ApOpt..39.3209R |s2cid=16434842 }}</ref> nevertheless, there is only a limited offering of commercially available [https://lightspace3d.com/ multifocal] near-eye displays.
Multifocal displays are a way of overcoming focal conflict. The principle of operation relies on availability of multiple image focal planes (screens), which from the perspective of a viewer are available simultaneously at all times. This gives the ability to accommodate eyes within the available range of focal distances and perceive realistic monocular focus (image blur) cues similarly to natural viewing conditions. Essentially multifocal displays discretize the depth dimension and split or slice the 3D content according to the available configuration of depth planes to minimize focal conflict. The topic of multifocal displays has been generously researched for at least several [http://bankslab.berkeley.edu/publications/Files/stereo_display_prototype04.pdf decades],<ref>{{Cite journal |last1=MacKenzie |first1=Kevin J. |last2=Hoffman |first2=David M. |last3=Watt |first3=Simon J. |date=2010-07-01 |title=Accommodation to multiple‐focal‐plane displays: Implications for improving stereoscopic displays and for accommodation control |url=https://jov.arvojournals.org/article.aspx?articleid=2191682 |journal=Journal of Vision |language=en |volume=10 |issue=8 |pages=22 |doi=10.1167/10.8.22 |pmid=20884597 |issn=1534-7362|doi-access=free }}</ref><ref>{{Cite journal |doi=10.1364/AO.39.003209 |title=Multifocal planes head-mounted displays |year=2000 |last1=Rolland |first1=Jannick P. |last2=Krueger |first2=Myron W. |last3=Goon |first3=Alexei |journal=Applied Optics |volume=39 |issue=19 |pages=3209–3215 |pmid=18349886 |bibcode=2000ApOpt..39.3209R |s2cid=16434842 }}</ref> nevertheless, there is only a limited offering of commercially available [https://lightspace3d.com/ multifocal] near-eye displays.