A team of researchers from Cambridge, Berkeley, MIT, and others has developed a novel method for boosting perceived contrast in VR headsets. The method exploits human stereo vision by intentionally mismatching elements of the view seen by each eye; the brain resolves the conflict in a way that boosts perceived contrast, the researchers say.

In the latest round of VR headsets, most major headset makers have moved from OLED displays to LCD displays. The latter offers greater pixel density, a reduced screen door effect, and likely lower cost, with the biggest trade-off being in contrast ratio. While OLED displays offer a wide contrast range and especially deep blacks, LCD displays in today’s headsets deliver a more ‘washed-out’ look, especially in darker scenes.

Researchers from Cambridge, Durham, Inria, Université Côte d’azur, Berkeley, Rennes, and MIT have developed a novel method which could help boost perceived contrast in VR headsets. The system is called DiCE, which stands for ‘Dichoptic Contrast Enhancement’. In a paper published earlier this year in the ACM Transactions on Graphics journal, the researchers say the method has “negligible computational cost and can be directly used in real-time VR rendering.”

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The researchers say that while tone mapping methods can boost perceived contrast in images, they are too slow and computationally expensive for practical use in VR rendering. Instead they propose a system which exploits the natural behavior of the human stereo vision system fool it into perceiving greater contrast.

Generally speaking, the goal in VR headsets is to always render stereo-accurate views; if the image shown to each eye has unexpected differences, it creates ‘binocular rivalry’ (AKA stereo-conflict) which can be visually uncomfortable as it creates a mismatch which is difficult for the brain to properly fuse into a coherent image. The DiCE method aims to exploit mismatched stereo images for enhanced contrast while preventing binocular rivalry. A video summary explains:

A key component to the method is figuring out how to render the images to enhance contrast without causing significant binocular rivalry. The researchers say they devised an experiment to determine the factors which lead to binocular rivalry, and then designed the stereo-based contrast enhancement to avoid those factors.

The main challenge of our approach is striking the right balance between contrast enhancement and visual discomfort caused by binocular rivalry. To address this challenge, we conducted a psychophysical experiment to test how content, observer, and tone curve parameters can influence binocular rivalry stemming from the dichoptic presentation. We found that the ratio of tone curve slopes can predict binocular rivalry letting us easily control the shape of the dichoptic tone curves.

After finding an approach which minimizes binocular rivalry, the researchers tested their findings, claiming “our results clearly show that our solution is more successful at enhancing contrast and at the same time much more efficient [than prior methods]. We also performed an evaluation in a VR setup where users indicate that our approach clearly improves contrast and depth compared to the baseline.”

The researchers believe the work is well suited for VR rendering, noting, “as tone mapping is usually a part of the rendering pipeline, our technique can be easily combined with existing VR/AR rendering at almost no [computational] cost.” The team even went so far as to publish a Unity Asset package for other researchers to play with.

The research team included Fangcheng Zhong, George Alex Koulieris, George Drettakis, Martin S. Banks, Mathieu Chambe, Fredo Durand, and Rafał K. Mantiuk.

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  • mAc

    OLED displays to LCD displays……. Please you are a professional Webpage… so don t call it Schnitzel. Call it LC-Display. THX

    • and you are obviously not a professional speller.

      • mAc

        yes you re right i am German

    • Kevin White

      This morning I drove my car, which has a CVT transmission, to the ATM machine.

    • benz145

      Ha this is a good point; granted I think adding the word ‘display’ helps someone understand who may not know what the acronym itself means.

      • Mike Porter

        “LCD display” is also correct. There are other displays today which are also based on liquid crystals such as LCoS and “LCD display
        ” is used to refer specifically to backlit nematic liquid crystal displays. For the same reason in the optics industry we use the terms “LCD light valves” and “LCD shutters” even though they are not displays since there is one “pixel”.

  • moogaloo

    Sounds good, but if this becomes widely adopted I hope there is always an option to switch of as I am cross eyed and tend to only look out of one eye at once.

    • aasdfa

      100% this, i have a lazy eye and was surprised that vr worked so well for me (3d works better in vr than the real world for me) and this might mess that up :(

      • victor

        maybe maybe not

      • Immersive Computing

        A genuine question, has VR improved your eyes? I have seen comments from people with similar conditions reporting it’s helpful and has trained their eye, or actually improved eyesight (one person said their optometrist asked them after recent eye test).

  • Hugo Zink

    Tonemapping isn’t “too expensive” at all. Stop restricting yourselves to immensely underpowered mobile headsets like the Quest and Gear VR.

    • Andrew Jakobs

      Uhm, Quest of Gear VR are 2 completely different mobile headsets.. And Quest is getting a big momentum, so if you are interested in developing VR for the masses, Quest is a good headset..

      • Hugo Zink

        I know they’re different headsets, but they’re both bound by the same mobile GPU restrictions which prevent post-processing from being viable. Quest is unsuitable for anything beyond tech demos or incredibly simplistic applications.

        When I see how much they had to strip down a game as light as *Robo Recall* of all things, it really opened my eyes.

        The Quest gaining momentum is evidently *not* a good thing, because now the “masses” think that low-quality mobile VR is “as good as it gets”. We figured out the wonders of tonemapping more than two decades ago, and yet thanks to the subversive marketing at Oculus, people like the author are convinced that tonemapping is “not computationally viable”. Absolutely unreal.

        • Andrew Jakobs

          I think you’re a snob if you think the Quest is only suitable for tech demos or incredibly simplistic applications. Yes it doesn’t have the graphical power a RTX2080ti has, but a lot of people also don’t have those GPU’s for desktop VR and do VR with a GTX1060.
          And the masses aren’t that stupid and also know the Quest is “as good as it get’s”, most people I speak (who aren’t VR enthousiasts) love what the Quest shows..
          You, as a VR enthousiast, have a different view on this than the masses..

          • d0x360

            The quest doesn’t even have the muscle of a GTX 960 so a 1060 is fine for most games as long as you aren’t running super sampling and plenty of PC gamers have systems with way better hardware than that. Steam hardware survey shows most people with 2060’s and 2070’s or the equiv which is again significantly more powerful than what’s going to be in a mobile device for years.

            GPU isn’t the only factor either. You seem to be forgetting the absolute massive difference in CPU power between even a 8 year old desktop CPU vs a modern ARM based one. Plus a PC generally has more and faster system memory.

  • Cool research, I would like to test it to see if it works well as they say

  • doug

    I’m a little surprised there’s not a link to a demo or even a youtube video viewable in an actual headset.

    • d0x360

      A video from inside a headset wouldn’t convey the effect

    • Fred

      You can see the effect just fine in the youtube video though.

  • Mike Porter

    Just read the paper and I’m surprised this hasn’t been thought of before.

    Any ideas if they have decided to patent this? Would be a shame to essentially do free beta-testing for them and then find out only one HMD brand is allowed this feature in the future.

  • d0x360

    I’m definitely not a fan of switching to LCD panels especially because I love horror games in VR and when it’s dark its basically impossible to see any detail because of the contrast and light bleed.

    I was recently playing the Vadar star wars game and there were multiple sections where I just had no idea what was happening because of it.

    I’ve actually held onto my original Rift and 3 sensors just because of it despite preferring the higher resolution and tracking in the rift s.

    • DjArcas

      The original rift was LCD not OLED, unless my memory’s failing me?

      • d0x360

        DK1 & 2 were basically phone screen LCD’s with a partition between the 2 sides but CV1 (Retail Rift) was 2 independent 90hz OLED panels.