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Thread: technical question regarding retro reflective screen Gain

  1. #11
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    Smile Good discussion!

    Quote Originally Posted by absolom7691 View Post
    Unfortunately with "3D" there is really very little movement forward. It seems the industry is stuck at stereoscopic displays.
    Agreed, although I'm at a loss to come up with another solution for 3D apart from a stereoscopic display. While the idea of capturing an interference pattern in a hologram to create a true 3D image is sexy as hell, I can't fathom a technology that could create such an interference pattern in real time at a high enough frame rate and resolution to enable 3D holographic video displays. Maybe they'll figure it out when we finally get our flying cars!

    Until something new comes along, VR is going to remain a novelty. It's fun to play with for a time. Hell, I even own an Oculus but the novelty wears off after a bit.
    I have the HTC vive and I'm still enjoying it. I think the big problem with current VR gaming is related to the games themselves and not the technology. They're still looking for that "killer app" that will break the genre wide open. I thought Beat Sabre might be the one, but I think it's popularity has peaked. A decent Star Wars-themed first-person shooter would probably work though.

    Regarding the tech: Flecom went to the IAAPA Expo in Orlando a year or two ago and they had a large room-scale multiplayer VR game room set up where players wore backpack-mounted gaming laptops and standard HTC Vive headsets. He said they had 30 people in a 40 ft square room all running around shooting one another in a "Call Of Duty" style game. From his description it sounded amazing. True, this isn't practical for a home setup, but they do have wireless options for the Vive now, and with the improvements in the controllers and the displays I think all that's missing is the right game. (Even though I'll admit that having enough open space will always be a challenge, unless you opt for a stand-in-place treadmill.)

    Quote Originally Posted by White-Light View Post
    Why do you need a mat and a projector when you can simply project the whole game into a pair of VR glasses such as Pimax or Occulus?
    I agree. If every player is wearing a VR headset the board itself isn't needed. But augmented reality *does* have a coolness factor all it's own, so maybe that's what they were going for? (And if so, then a single 2D overhead projector will give you pseudo-3D augmented reality for a lot less money.)

    I'd speculate a large proportion of the light will still reflect off in other directions and be lost, resulting in a dim image that fluctuates in brightness according to the angle of incidence.
    Yup. For a typical high-reflectivity glass-bead screen, I think you'd be looking at a usable viewing angle (well, a cone) of about 15 degrees. If you reduce the brightness of the screen you can increase that of course, but now you run into two problems: one, the image will get dimmer as more light is scattered in other directions and is lost, and two, the polarization difference will start to smear together which will spoil the image quality.

    The light lost from the projection by the other players, especially the guy sat opposite is surely going to be reflected into your vision and cause some kind of flare or ghosting
    Bingo. This, to me, is the biggest challenge of the entire setup. I just don't see how you could make this work with people sitting on opposite sides of the table and both projecting their own views down to the screen.

    unless they have done something trick with the polarisation timings so other players projections are either on the opposite polarity or fall into the brief switching period between polarities where no light is let through
    Hmmm. So, hypothetically, let's take this in an entirely different direction: Assume you have LCD shutter goggles on each player (max of 4) and say you run the master overhead display at some ridiculously high frame rate - call it 240 frames per second. Further assume that the computer/graphics card driving this can calculate 4 separate 3D views of the board in real time based on head-tracking position data from each player's goggles. (Dual or Quad RTX 2080 with SLI should do it. Probably quad GTX 1070 SLI would be enough.)

    Now you interleave the displayed frames like this: Player one - left eye view. Player two - left eye view. Player three - left eye view. Player four - left eye view. And now back to Player one - RIGHT eye view. And so on... Close the shutters on each set of goggles whenever another player's view is being shown. You would then get 30 frames per second for each eye, 60 frames per second for each player, and a total frame rate of 240 frames per second.

    Each player would still have full view of the game board so the cool augmented reality feature is preserved (so you can use your favorite figurines or whatever) and as long as the overhead projector is bright enough you can still see well enough even with the LCD shutters closed for 75% of the time. You could even include "hidden" objects that are unique to each player. I think this would end up being more affordable than having 4 separate computers each driving a VR headset.

    The main issue I see with this arrangement would be the super-brief exposure time for each player. (1/240th of a second per eye)
    I know for a single exposure the response time is around 10 ms. This would be closer to 4 ms, but it's also a repeating image, so it might still work.
    Would probably flicker like hell though. Sigh. Maybe it's not such a hot idea after all...

    it seems to me this is an attempt to reinvent the wheel, possibly in the aim of bringing a lower cost solution. However, the issue with reinventing the wheel, is you need to ensure it still comes out round.
    Hehe! I like that analogy. Yeah, the more I think about this whole thing, the more I'm convinced that it's a non-starter. And to try to do it WIRELESSLY just adds that much more complexity. I doubt we'll see this in Best Buy anytime soon...

    Adam

  2. #12
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    Quote Originally Posted by buffo View Post
    Agreed, although I'm at a loss to come up with another solution for 3D apart from a stereoscopic display. While the idea of capturing an interference pattern in a hologram to create a true 3D image is sexy as hell, I can't fathom a technology that could create such an interference pattern in real time at a high enough frame rate and resolution to enable 3D holographic video displays. Maybe they'll figure it out when we finally get our flying cars!
    I agree whole heartedly with this. It's a shame that we only have stereoscopic displays because we'll always be limited by that.

    I think the big problem with current VR gaming is related to the games themselves and not the technology. They're still looking for that "killer app" that will break the genre wide open.
    I halfway agree with this. The problem I see is that with VR, there needs to be so much more than just 3D visuals. The graphics are immersive and I will admit, when I first put on my Oculus, I thought it was cool as hell. The visuals were amazing and I felt like my head was in the place I saw. The problem was the rest of it... Not as immersive as I would like.

    Yes though, the killer app has yet to surface. Robo Recall was one of best I played and given the number of games out there, I have only played a few that were any good. Unfortunately, this is like credit. You need get credit to establish credit but you can't get credit without having established credit. No programmers want to commit to the genre because it hasn't broken out yet but it can't until there are good programmers releasing titles....

    I think all that's missing is the right game. (Even though I'll admit that having enough open space will always be a challenge, unless you opt for a stand-in-place treadmill.)
    I can get behind the thought here. Open space would be the one of the last pieces of the puzzle. Better haptic feedback would be great too. Of course, this comes back to the technology. Speaking of treadmills... skip to 9:10... https://www.youtube.com/watch?v=qh2UdRKNqH4 Looks promising.

  3. #13
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    Quote Originally Posted by buffo View Post
    Agreed, although I'm at a loss to come up with another solution for 3D apart from a stereoscopic display. While the idea of capturing an interference pattern in a hologram to create a true 3D image is sexy as hell, I can't fathom a technology that could create such an interference pattern in real time at a high enough frame rate and resolution to enable 3D holographic video displays. Maybe they'll figure it out when we finally get our flying cars!

    Adam
    Check out what VividQ is doing. https://www.vivid-q.com/

  4. #14
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    Quote Originally Posted by absolom7691 View Post
    Robo Recall was one of best I played and given the number of games out there, I have only played a few that were any good.
    I haven't tried that one yet, but based on a quick peek it looks really nice. I've enjoyed Raw Data a great deal even though the setting isn't nearly as photo-realistic.

    First-person shooters are already well-represented in VR, but I'd like to see the technology used for other games. Imagine Roller Coaster Tycoon in VR, for example. (And no, not just for the ability to ride the rides.)

    Better haptic feedback would be great too.
    Have you seen the new "knuckles" controllers from Valve? They don't really improve on the haptic feedback much (they use the same vibration feedback that the Vive controllers have), but they *do* allow for tracking of individual fingers, which opens up a lot of interesting options. I'm thinking about upgrading my VR setup this fall and will probably get a set of these controllers.

    Speaking of treadmills... skip to 9:10... https://www.youtube.com/watch?v=qh2UdRKNqH4 Looks promising.
    I've seen a few different versions of the "treadmill of treadmills" design like that. Honestly though, I think it's probably too expensive for anything outside of a commercial video arcade. I think the passive systems with your feet sliding around on a polished bowl surface while you are suspended from an overhead arm (like you see at the start of the video you linked to) is probably the most cost-effective option. I think they could get the price of that rig down to a few hundred dollars at some point.

    Quote Originally Posted by Eidetic View Post
    Check out what VividQ is doing. https://www.vivid-q.com/
    Wow... I didn't think the hardware needed to generate a real-time diffraction hologram at 60 FPS existed yet. True, they're not calculating each point, but rather frame slices, so they are cheating a bit (it's not perfect), but from the videos I watched it sure looked good enough to me. Absolutely mind-blowing to think about all the calculations going on... (I found this overview presentation to be most informative.)

    Limits appear to be the size of the spacial light modulator (LCoS), computational overhead, and cost. Guessing that illumination power is also limited based on the small size of the LCoS. I did see where they just got nearly 2/3 of a million dollars in venture capital though, so someone must think this idea has potential!

    Would love to see this in person.

    Adam

  5. #15
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    I saw it at Photonics West a few months ago. Very impressive, but also very limited eye box and field of view. I'm working with them on the former, but holographic light guides are not really a good solution for near-eye displays. That doesn't stop a company like Digilens from raising many millions over the years and recently to promote them. After 20 years of trying, nothing but prototypes and a single sale to Rockwell six years ago. 13 years of my career spent making those prototypes, but I digress.

  6. #16
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    Quote Originally Posted by Eidetic View Post
    13 years of my career spent making those prototypes, but I digress.
    Seriously? I had no idea! I'd love to hear more about this sometime, as would several others I'm sure. (SELEM?)

    Adam

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