Is there any AR headgear which displays the real world optically and can selectively darken the real world? Magic Leap pretended to do that, but now it appears they can't. You could, of course, do it by focusing the real scene on a focal plane, like a camera, using a monochrome LCD panel as a shutter, and refocusing the scene to infinity. But the optics for that require some length, which means bulky headgear like night vision glasses. Maybe with nonlinear optics or something similarly exotic it might be possible. But if there was a easy way to do this, DoD would be using it for night vision gear.
There is actually a solution (EDIT: nope, see replies), but it's tricky: If you stack two sheets of polarizing filters on top of each other, then rotate them, you can get them to pass all light at 0 degrees rotation and block all light at 90 degrees rotation. It's like special paper that adjusts brightness depending on how much it's rotated relative to the sheet of paper behind it. https://www.amazon.com/Educational-Innovations-Polarizing-Fi...
So you could imagine cutting a series of circular polarizing filters and using them as "pixels". If you had a grid of 800x600 of these tiny filters, and a way to control them at 60 fps, you'd have a very convincing way of "displaying dark" in real time.
It'd require some difficult R&D to be viable. Controlling 800x600 = 480,000 tiny surfaces at 60fps would take some clever mechanics, to put it mildly. Maybe it won't ever be viable, but at least there's theoretically a way to do this.
A minor problem with this approach is that the polarizing filter may affect the colors behind it. But humans are very good at adapting to a constant color overlay, so it might not be an issue.
(Also, if the pixels are dense enough I imagine you'll get diffraction.)
Here's is Michael Abrash's better explanation:
>“But wait,” you say (as I did when I realized the problem), “you can just put an LCD screen with the same resolution on the outside of the glasses, and use it to block real-world pixels however you like.” That’s a clever idea, but it doesn’t work. You can’t focus on an LCD screen an inch away (and you wouldn’t want to, anyway, since everything interesting in the real world is more than an inch away), so a pixel at that distance would show up as a translucent blob several degrees across, just as a speck of dirt on your glasses shows up as a blurry circle, not a sharp point. It’s true that you can black out an area of the real world by occluding many pixels, but that black area will have a wide, fuzzy border trailing off around its edges. That could well be useful for improving contrast in specific regions of the screen (behind HUD elements, for example), but it’s of no use when trying to stencil a virtual object into the real world so it appears to fit seamlessly.
http://blogs.valvesoftware.com/abrash/why-you-wont-see-hard-...
https://www.youtube.com/watch?v=bmHSIEx69TQ&feature=youtu.be...
That approach is devastatingly hard, but probably the best way to do it.
Right, that's how all existing HMD systems work - but generally not with the whole FOV re-rendered so it's not so cut and dry.
Note that such a system doesn't give you black ever. It gives you muddy [insert lens color on the grey spectrum].
The case you describe ends up with what is practically an opaque lens that is replicating the environment that is not virtual. So you might as well just use VR with camera pass through at that point.
One idea that comes to mind is that a regular screen leaks light. If you adjust the brightness on your laptop as low as it will go, then display a black image, there's still a massive difference between what you see there vs when the screen is completely powered off. But if you take two sheets of polarizing filter and stick them in front of your screen, you can get almost perfect blackness. That's why I thought it was a different idea, since the difference is so dramatic. You can block almost all the light, whereas a regular screen doesn't seem to be able to get that kind of contrast.
Yes, yes, it's still not a hologram, but the popularized version of holograms (from things like star wars) is still the best way to think about AR display.
If you can show SOME black, text legibility becomes a lot easier. Everything can look way better, even if the world always shines through enough to see it.
If you can show PURE black, enough to ACTUALLY obscure the world, now you can erase stuff. Like indicator lights, panopticon optics, and people.
[1] http://media.bestofmicro.com/V/H/563597/original/Meta-Collab... [2] http://www.roadtovr.com/wp-content/uploads/2015/10/magic-lea... [3] https://winblogs.azureedge.net/devices/2016/02/MSHoloLens_Mi...
Anyone seen a TFT "filter" mounted on the front of a transparent OLED "backlight"?
Yes I'm sure they must have thought of it. Wonder what the issue is.
[edit] I read the explanation further down now
It can give pure black if the polarising plates and liquid crystal is accurate enough.
Sounds very suspicious to me.
Profitable startups with hockey stick like growth can't even raise a couple million...damn.
They've said they have a solution, and it's more optical illusion than optics. They don't darken the real world, but will make you perceive something similar.
What about those windows where, at a press of a button, they turn relatively opaque?
http://blogs.valvesoftware.com/abrash/why-you-wont-see-hard-...
Two of the major unsolved problems he talks about are latency and the ability to draw black - I would be surprised if magic leap had solved both of these alone and in secret.
Their vapid press releases didn't inspire confidence either.
A bit of a tangent, but: for some people, it's impossible for VR to avoid making them feel sick. It's fundamental to them wearing a VR headset rather than a technical challenge to be overcome. It's related to the fact that VR headsets can't project photons from arbitrary positions with arbitrary angles towards your eyes (i.e. a screen is planar, but the real world is a 3D volume). Turns out, evolution has ensured our bodies are very good at determining the difference between a screen's projection and the real world, resulting in a sick feeling when there's a mismatch.
I think that when people accept it's inevitable some subset of users will get sick, the VR ecosystem will grow at a faster rate.
That might be harder than getting a functional light field display, though.
What I was picturing was: - LCD display - Patterned IR image projected onto eye - Camera to read IR image on the back of retina, to figure out current focal length of cornea - Realtime chip to adjust LCD display based on focal depth, to simulate light field image.
... The real issue is that response latency would have to be <10ms probably to avoid being disorienting.
Here's some interesting reading:
https://en.wikipedia.org/wiki/Simulator_sickness
https://news.ycombinator.com/item?id=5265985
> In a study conducted by U.S. Army Research Institute for the Behavioral and Social Sciences in a report published May 1995 titled "Technical Report 1027 - Simulator Sickness in Virtual Environments", out of 742 pilot exposures from 11 military flight simulators, "approximately half of the pilots (334) reported post-effects of some kind: 250 (34%) reported that symptoms dissipated in less than 1 hour, 44 (6%) reported that symptoms lasted longer than 4 hours, and 28 (4%) reported that symptoms lasted longer than 6 hours. There were also 4 (1%) reported cases of spontaneously occurring flashbacks."
Simulator Sickness in Virtual Environments (PDF): http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA295861
Some interesting quotes from the report:
Expected incidence and severity of simulator sickness in virtual environments
> In an analysis of data from 10 U.S. Navy and Marine Corps flight simulators, Kennedy, Lilienthal, Berbaum, Baltzley, and McCauley (1989) found that approximately 20% to 40% of military pilots indicated at least one symptom following simulator exposure. McCauley and Sharkey (1992) pointed out that pilots tend to be less susceptible to motion sickness than the general population due to a self-selection process based on their resistance to motion sickness. Since VE technologies will be aimed at a more general population, such selection against sickness may not occur. Thus, McCauley and Sharkey suggested that sickness may be more common in virtual environments than in simulators.
Findings
> Although there is debate as to the exact cause or causes of simulator sickness, a primary suspected cause is inconsistent information about body orientation and motion received by the different senses, known as the cue conflict theory. For example, the visual system may perceive that the body is moving rapidly, while the vestibular system perceives that the body is stationary. Inconsistent, non-natural information within a single sense has also been prominent among suggested causes.
> Although a large contingent of researchers believe the cue conflict theory explains simulator sickness, an alternative theory was reviewed as well. Forty factors shown or believed to influence the occurrence or severity of simulator sickness were identified. Future research is proposed.
Vection
> One phenomenon closely involved with simulator sickness is that of illusory self-motion, known as vection. Kennedy et a1. (1988) stated that visual representations of motion have been shown to affect the vestibular system. Thus, they conclude that the motion patterns represented in the visual displays of simulators may exert strong influences on the vestibular system. Kennedy, Berbaum, et al. (1993) stated that the impression of vection produced in a simulator determines both the realism of the simulator experience and how much the simulator promotes sickness. They suggested that the most basic level of realism is determined by the strength of vection induced by a stimulus. For a stimulus which produces a strong sense of vection, correspondence between the simulated and real-world stimuli determines whether or not the stimulus leads to sickness. Displays which produce strong vestibular effects are likely to produce the most simulator sickness (Kennedy, et al., 1988). Thus, Hettinger et al. (1990) hypothesized that vection must be experienced before sickness can occur in fixed-base simulators.
> While viewing each of three 15-minute motion displays, subjects rated the strength of experienced feelings of vection using a potentiometer. In addition, before the first display and after each of the three displays, the subjects completed a questionnaire which addressed symptoms of simulator sickness. Of the 15 subjects, 10 were classified as sick, based on their questionnaire score. As for vection, subjects tended to report either a great deal of vection or none at all. In relating vection to sickness, it was found that of the 5 subjects who reported no vection, only 1 became sick; of the remaining 10 subjects who had experienced vection, 8 became sick. Based on their results, Hettinger et al. concluded that visual displays that produce vection are more likely to produce simulator sickness. It is also likely that individuals who are prone to experience vection may be prone to experience sickness. It was mentioned earlier in this report that a wider field- of-view produces more vection and, thus, is believed to increase the incidence and severity of sickness (Kennedy et al., 1989). Anderson and Braunstein (1985), however, induced vection using only a small portion of the central visual field and 30% of their subjects experienced motion sickness.
I'd be interested to hear some testimonials on how it affects people though. One of the interesting things about VR is finding out the myriad of different ways people are sensitive to small phenomena.
I own a Vive, and get sick using that after half an hour maybe (even though it's not too bad and I can keep using it), and it takes me a few hours to "reset" afterwards.
I don't get sick in 3D movies (but I don't enjoy them, and never choose to see one in 3D if there's an alternative.
The reason I don't get sick in 3D movies I assume is because it's still just a screen, and any head movement I make is still 100% "responsive", with no delay or mismatch.
Edit: Sorry, I read your response a bit lazily. Yes, it's not related to vergence-accommodation, at least not exclusively.
If it works near a closeline blowing in the wind that's really hard and impressive.
In AR, you're competing with on latency with the human visual system that you're trying to augment, which is a race you can't win.
The only thing you can do is try to be very fast (<= 10 ms) so the latency becomes unnoticeable. Unfortunately right now this isn't possible unless you custom-engineer everything in your vision path optimized for latency. Fun R&D project but enormously time- and capital intensive with no guarantees for success.
VR is a much tougher nut to crack.
And the PS no? I think that all the VR system will (optionally) do this to reduce the processing power needed.
From my understanding this won't do anything to reduce power processing, it's all about reducing latency. That final transform happens at the last moment, with the most up-to-date head tracking information. I kind of figured it happened in the headset hardware itself in order to reduce the latency as much as possible.
https://developer3.oculus.com/blog/asynchronous-timewarp-exa...
I sort of assumed it was like a stack of images in the Z plane. So not only are they doing everything you mentioned, they are also rendering the 3D scene in slices?
Magic Leap was always a much more difficult problem... they have to respond to a user's head movement, parse the scene the user is looking at (which could be anything), figure out what to draw and where to draw it on the user's environment, then render, all in the same 14-20ms window.
Compounding that they have to do it with a much weaker CPU/GPU/battery than Oculus and friends, which use a phone, or are tethered to a PC with a $1,000 GPU. You wear Magic Leap on your head, no cables.
On its face I was always sort of surprised to hear about the good demos; it always seemed like such a difficult problem, and I know the VR folks are having a tough enough time with it.