3D "Pop-out" clarified and "violations" that lead to discomfortGeneral


  1. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

    I spoke with my neighborhood stereoscopy expert (30-years of experience, custom-built camera rig, home-theater setup with polarized projectors, etc.) and learned quite a bit about 3D imagery. Thought I'd share some general facts and other factors that cause eye strain and headaches.

    Regarding images that pop out: already proven possible with the screen technology. But will the phone's camera be able to capture a subject and then show it popping out? Most likely, but not guaranteed.

    In another thread, I incorrectly concluded that the focal point determines the threshold where things pop out or appear behind the screen. Actually that threshold is fixed based on the distance between the lens and the offset of the sensors behind the lenses. I have no visibility into how the E3D's sensors are set, so there's no way to guess what the zero parallax line lies. However, once the phone is released, it will be trivial to determine this by taking a picture of a ruler (or tape measure) that extends from the camera. If you overlay the stereo images in photoshop, the ruler will appear as a thin X. Where the convergence of the X is on the ruler will be the zero parallax line (aka point of convergence).

    Objects farther from zero parallax will appear behind the display; objects closer will appear to pop out from the screen.

    This article makes it really simple to understand:
    STEREOSCOPIC (3D) FILMMAKING OVERVIEW Part 2

    Commonly, the distance between cameras (aka the stereo base) is set to the human interocular distance (distance between human eyes), which is about 2.5". But there's no real reason why this needs to be enforced; it really depends on the scale of your subject. If you're taking a picture of insects, your camera lenses should be much closer together. If you're taking a picture of the grand canyon, the cameras should be very far apart. Again, that article above talks about why you may want to use cameras that are further apart. But a moot point for E3D since we can't adjust the cameras. But given that the Evo's cameras are kinda close together, the best 3D shots will be with subjects closer to the screen.

    Onto the discomfort.

    My source tells me that pop-out is actually not very desirable for two reasons:

    1) it causes eye strain due to the need to focus on a point close to the eyes (cross-eye). Prolonged cross-eye is not comfortable.

    2) when a pop-out object is cropped by the edge of the screen, our brain freaks out because it conflicts with reality. The object should appear in front of the edge and not be cut off. This is considered a violation of good stereoscopy and should be avoided.

    Another violation is an exaggeration of depth where the distance between stereo images exceeds the interocular distance. This isn't going to be a problem with the Evo 3D's images, but this is much more common in a theater. Film producers sometimes push the limit to try to give the scene maximum depth by spacing out the parallax images. This can trigger instant headaches. Also if you sit too close to the screen, the problem becomes amplified.

    He rattled off a few more violations that I can't recall, but basically he says that the violations are what make 3D gimmicky, and it's also responsible for the discomfort and inability to see in 3D for some subset of the public. When the rules of stereoscopy are obeyed, the results are spectacular and comfortable to view, because they simulate depth realistically.

    Just sharing for those of you actually interested in the 3D capabilities of the phone.

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  2. BenChase7

    BenChase7 VIP Member VIP Member

    Thanks for this (and your other valuable info). Damn, we have great Mods here.
    bobby2478, jroc and RichboyJhae like this.
  3. Emmexx

    Emmexx Well-Known Member

    Much obliged, Novox!
  4. ImpulsebuyerNy

    ImpulsebuyerNy Well-Known Member

    Nice write up!

    I agree the dam Nintendo 3DS on display in gamestop only took me 10mins before i got a headache , hope the Evo 3D isn't that bad !! :(
  5. Vanquished

    Vanquished Well-Known Member

    Are you refering to 3D viewing or taking 3D pictures/movies here? If I understand this part correctly, the E3D shouldn't cause problems with headaches?
  6. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

    I was talking about 3D images/photos captured by 3vo's cameras, and specifically about violating the "3D window," which is the comfortable near and far distance based on the layout of the cameras and sensors. That article I linked to explains this. It COULD happen with the 3VO in rare situations (like trying to exaggerate a pop-out) but under normal applications, it should be ok. I was trying to say that movie makers will try to increase the depth of the movie without the proper camera alignment, or artificially increase the parallax via software. These violations are built-in (hardcoded) to the film and cannot be corrected by the phone. Phone is just going to play it back as-is. So.... blame the movie maker, not the player.
    Vanquished likes this.
  7. EarlyMon

    EarlyMon The PearlyMon Moderator

    Being the ostentatious one, I'll speak up - on behalf of mod staff, thanks for your on-going support and appreciation - it makes our days!
  8. Rob

    Rob I'm tellin' mommy on you! Administrator

    Wow. What a comprehensive and interesting analysis. I think this definitely deserves some front page Phandroid love. Not all consumers will be interested, but I can tell you that any 3D Game/App developers should read it closely to understand and obey the rules, inherently creating a better experience for their users!
    jroc, yourfriendmat and EarlyMon like this.
  9. CriticalMass

    CriticalMass Well-Known Member

    Unfortunately none of this will matter if the camera quality is the same as most smart phones out there.

    I don't understand why anyone cares about 1080p recording if the 1080p imagery is filled with hotspots. The whole point of this kind of technology is a perfectly clean image.
  10. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

    To that, I would say there's a time and place for everything. I'm a photographer, and I would never use my Evo to do a photoshoot at a wedding, obviously, but we've seen plenty of good content come from mobile devices. Sometimes a technical limitation can be overcome with artistic creativity.
    fattank likes this.
  11. jroc

    jroc Well-Known Member

    Nice write up. The last few writes up you've done have been nice. And congrats to the Mod title. Every time I turn around a familiar face is a Mod...
    novox77 likes this.
  12. fattank

    fattank Well-Known Member

    Excellent; it's great you've further verified this! Of course this is assuming the lenses do not have any sort of swivel (that is to say, assume some arbitrary, fixed, immutable flat plane bisects both lenses). This assumption (and a few others) also underlie my "further uses of the 3D camera" ideas post from earlier. A ruler is also largely unnecessary if the distance between lenses is known (and it can be measured most accurately on a minute scale without involving spatial discrepancies, optical distortions such as barrel/pincusion and other radial aberration).

    Further source(s) of discomfort may very well stem from the screen technology itself. The lower the resolution, the more the eyes attempt to re-focus on what is perceived as blur. For eyes "used to" viewing 2D images on various screens, our eyes may have become used to this, but for 3D, this problem may recur -- especially if "qHD" resolution relies on some trick like 960/2=480 for each eye like the 3DS (400/2). Pixel depth aside, the 3D effect (and therefore the depth of field) will change depending on the tilt of the device away from the "sweet spot" causing further binocular disparity changes and leading to convergence/deconvergence adjustments as our eyes attempt to again re-acclimate to the new field depth.

    This is my take on it, but I agree these factors may be trivial. Then again, they could be the chief determining factors of "discomfort" -- the falloff and overaccentuated paralax may only account for suspension of believability and "impact" of the effect, rather than the actual strain.
  13. fattank

    fattank Well-Known Member

    Indeed, or mathematical (DSP) creativity. I degrain my HD2's photos using automated computer-side temporal denoising. The phone bursts 3-5 pictures, which are then de-noised incredibly well on my computer.

    The deal is to take med/high-ISO pictures to preserve high amounts of detail (in low-light settings this is especially paramount) and reduce exposure-time-induced blur at the cost of additional random grain. Ideally, this can be implemented on the device itself (on the GPU no less, for real-time low-power processing). Obviously, temporally-corrected de-shake and such have been realized for conventional cameras.

    What's truly exciting to me are the new possibilities (and accuracy!) that comes with a 2-camera setup!
  14. bobby2478

    bobby2478 Well-Known Member

    Thanks for the very comprehensive write up! I know myself, as well as many others, appreciates the very helpful info!

    One quick question: Based on what you know, do you feel the Evo3D will cause problems with headaches/eye strain under normal use with 3D enabled? I'm not planning on buying the Evo3D solely for the 3D aspect, it's more of an added bonus, but if this is going to be uncomfortable and cause headaches/eye strain I may need to skip this phone all together. That, or as I understand it, you can disable 3D mode and have it run in 2D, thereby eliminating any of these issues.

    I'll likely buy the phone anyway and if I experience issues, I can return it within 30 days and get something else. But your opinion on what to expect would be greatly helpful. Thanks!!
  15. novox77

    novox77 Leeeroy Jennnkinnns! VIP Member

    Based on feedback I've seen from other forum users and their experiences with other 3D screens, I can safely say that....

    ...I have no idea if you will get headaches/eye strain. Aside from technical reasons caused by the 3D screen, there are also perceptual issues that vary from person-to-person. Think of it like motion sickness. There's a wide range of tolerance.

    If you've generally had good experience with 3D in a theater or other stereoscopic media, you'll likely have no issues with the Evo 3D.
    bobby2478 likes this.
  16. bobby2478

    bobby2478 Well-Known Member

    That makes sense, thank you. I personally don't have any experience with 3D via either a theater or stereoscopic media, so I'm not sure what to expect. It makes sense though that this will vary by person, some people won't experience any issues and some others may be very sensitive and thus much more suceptible to issues.

    My main reason for the question is all the talk I've heard about the Nintendo 3Ds (I believe that's what it's called), and how there has supposedly been widespread issues with people complaining of headaches/eye strain. That talk may have been overblown, but I'm not sure to what extent this problem has been confirmed or not.

    Since the Evo3D uses a similar 3D effect (screen only, no glasses), I was wondering if this would also exhibit similar problems. Of course even if it did, as long as you can disable the 3D mode and have things in 2D mode, this would eliminate any issues you might experience.

    Thanks again for your feedback and knowledge!
  17. ArmageddonX

    ArmageddonX Well-Known Member

    Nintendo has come out and said:
    3D is dangerous / not dangerous: Nintendo 3DS warning label edition -- Engadget

    Also,
    http://news.discovery.com/tech/nintendo-issues-age-warning-3d-101230.html

    I don't know about you guys, but I will certainly make sure my Son doesn't watch anything on my Evo3D for extended periods of time. Better safe than sorry...

    Again, this effect may be different than the EVO3D, so the article only pertains to the Nintendo 3DS. I'm sure if there is an issue with the Evo3D that HTC will make sure we are well informed.
    bobby2478 likes this.
  18. bobby2478

    bobby2478 Well-Known Member

    Very good point. Of course, provided you can toggle between 2D and 3D, you could keep your device in 2D mode most of the time, then enable 3D when you want to use it, like look at 3D movies or photos, etc.

    From the sounds of it, the 3D effect doesn't do much for normal operation of the phone, you most realize the 3D when playing 3D games, watching 3D videos, etc. It doesn't sound like you'll really notice 3D when you're just using your phone for surfing the web, sending texts, etc.
  19. ArmageddonX

    ArmageddonX Well-Known Member

    From my understanding the 3D is only (automatically) turned on exclusively for 3D movies, 3D pictures, & 3D games and remains turned off (automatically) for all other functions.

    I sincerely hope thats true and the 3D does not pertain to Menu/Web/Text. I do not want *everything* or even most things to be in 3D all the time.

    This is an issue that I think will probably have to be clarified to people over and over again in the future.
  20. bobby2478

    bobby2478 Well-Known Member

    I would like a better understanding of whether the 3D is enabled "automatically", or if you as the user can "manually toggle" between 2D and 3D. We likely won't know for sure until there is a phone available for extensive hands-on reviews.

    Does anyone have any insight into whether you can manually toggle the 3D mode on/off, or if the Evo3D will automatically enable and disable this feature?
  21. cobalt

    cobalt Well-Known Member

    Nah, I think you're pretty safe. They'd have to invent some sort of depth for UI or web elements, and it'd largely look ridiculous if not downright painful to focus on so many depths. Plus, since the autosteroscopy doesn't work in portrait mode, they'd have to be disabling it all the time anyway. Maybe you'll see someone put something like a 3D-ifying web browser as a novelty in the Android Market, but it would pretty much be so far down the "gimmick" route it wouldn't be the default anytime in the next few years.

    Plus, I'll predict they've got a convenient way to disable stereo on the display. Maybe even have a global setting for it.
  22. EarlyMon

    EarlyMon The PearlyMon Moderator

    There's a CTIA demo of Sense floating around here - it's about 6 minutes long - the UI is 2D and crystal clear.
  23. themuffinman75

    themuffinman75 Well-Known Member

    There is no manual toggle for viewing 3d content, its all in the software. It will automatically detect any 3d content, so if you aren't interested in 3d content then leave the specific 3d content alone and you will be fine.
  24. cobalt

    cobalt Well-Known Member

    Well, we've been told there's no hardware switch to disable it, but that doesn't rule out a software-based manual toggle. I expect at least a global stereo-kill switch, but even if I'm wrong about that, then I expect most apps will include a setting to control/disable it.

    (Here's my reasoning: Think about the 3DS: the tolerable amount of stereo separation varies from game to game, and for some games, even though it supports stereo-3D, many users may not want to play it in stereo-3D. As much gushing there's been in the press over the existence and support of that 3DS slider, I think HTC couldn't possibly ignore that rather important lesson. As such, even if they couldn't fit a hardware slider on there, I'd expect them to have a software control, even if it's just to force stereo off. And if they managed to mess that up and include no manual controls, the individual application developers that support stereo will be smart enough to include one.)
  25. ArmageddonX

    ArmageddonX Well-Known Member

    I'm pretty sure the Nintendo 3DS had a "Parental Control" setting so you could disable the 3D with a password.
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