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Why Stereoscopic 3D is Awesome

Manufacturer: PC Perspective

And Why the Industry Misses the Point

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I am going to take a somewhat unpopular stance: I really like stereoscopic 3D. I also expect to change your mind and get you excited about stereoscopic 3D too - unless of course a circumstance such as monovision interferes with your ability to see 3D at all. I expect to accomplish where the industry has failed simply because I will not ignore the benefits of 3D in my explanation.

Firstly - we see a crisp image when our brain is more clearly able to make out objects in a scene.

We typically have two major methods of increasing the crispness of an image: we either increase the resolution or we increase the contrast of the picture. As resolution increases we receive a finer grid of positional information to place and contain the objects in the scene. As contrast increases we receive a wider difference between the brightest points and the darkest points from a scene which prevents objects from blending together in a mess of grey.

We are also able to experience depth information by comparing the parallax effect across both of our eyes. We are able to encapsulate each object into a 3D volume and position each capsule a more defined distance apart. Encapsulated objects appear crisper because we can more clearly see them as sharply defined independent objects.

Be careful with this stereoscopic 3D image. To see the 3D effect you must slowly cross your eyes until the two images align in the center. This should only be attempted by adults with fully developed eyes and without prior medical conditions. Also, sit a comfortable distance away so you do not need to cross your eyes too far inward and rest your eyes until they no longer feel strained. In short - do not pull an eye muscle or something. Use common sense. Also move your mouse cursor far away from the image as it will break your focusing lock and click on the image to make it full sized.

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Again, be careful when crossing your eyes to see stereoscopic 3D and relax them when you are done.

The above image is a scene from Unreal Tournament 3 laid out in a cross-eyed 3D format. If you are safely able to experience the 3D image then I would like you to pay careful attention to how crisp the 3D image appeared. Compare this level of crispness to either the left or right eye image by itself.

Which has the crisper picture quality?

That is basically why 3D is awesome: it makes your picture quality appear substantially better by giving your brain more information about the object. This effect can also play with how the brain perceives the world you present it: similar to how HDR tonal mapping plays with exposure ranges we cannot see and infrared photography plays with colors we cannot see to modify the photograph - which we can see - for surreal effects.

So what goes terribly wrong? Read on to the article to find out.

Let us completely ignore the difficulty of capturing a 3D image and pretend that we have a completely flawless method of getting from the camera or animation program to your display. Getting the information from the display to your eye is terribly difficult and almost always involves reducing your picture quality in order to make it happen.

Many televisions with passive glasses polarize every second line an alternating pattern of clockwise and counterclockwise circular polarizations. The passive glasses contain filters which block the incorrect polarization and allow the correct one through. If you were to wear these glasses and close one eye you would notice that every second line appears dark in what almost looks like a corduroy pattern.

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Why waste good work? Here's another UT3 3D pic.

So to get extra crispness you reduce your resolution crispness by a factor of 2. Sound counter-productive?

How about active shutter glasses? Well each pixel sends out an alternating image for each eye which the glasses correspondingly block in time. The problem is that you are losing at least half of the contrast which the TV is capable of providing and that assumes the manufacturer is able to prevent the wrong eye from “cross-talking” and leaking through the unintended lens.

What about passive holographic displays like on the Nintendo 3DS or upcoming glasses-free TVs? How these TVs work is they designate a pixel to belong to a specific eye and they use a lenticular effect to basically aim the pixel in the proper eye. You once again lose resolution on the display and get a holographic shimmery distortion over everything to boot.

Heck - just thinking about this is enough to make me go cross-eyed.

So we have not really found too many ways to get full quality 3D into your eyes without defeating the whole purpose in the process. Eventually we should find a way: whether it is the Oculus Rift, some form of laser display, or a lens made of distilled unicorn tears? Who knows?

Maybe we can trick the brain into believing in 3D some other way? Your brain can also acquire depth information by paying attention to the slight bobbling of your head. Some research has been done to track your head motions and adjust virtual objects in the scene correspondingly which your brain could use to build depth information. There was an old video demonstration of this effect using Wii remote hackery where it was even possible to make targets appear as if they were coming out of the screen and at the viewer despite being a completely 2D display. Maybe we need to completely rethink the problem in order to comfortably use 3D to increase image crispness? Maybe what we have just needs to get better?

There is a purpose for stereoscopic 3D. It just does not get considered very often...

Especially not by those who promote it.

As an aside: Remember how you can create surreal effects with 3D? Another problem with 3D is that some people get an equivalent of motion sickness. If you have not picked up on it by now: the human brain processes everything you do at all times. The brain is way more complicated than we give it credit for.

If you give your brain nonsensical 3D it will attempt to make sense of it in any way it can. One possible conclusion that your brain can reach is that the imagery is not the problem but instead that you are under the influence of a neurotoxin and cannot properly process the image. Of course you are not poisoned but your subconscious can think of no other solution. As such your brain will kick into survival mode and make you nauseous to eject the contents of your stomach.

This is just one example of how playing games with how your brain perceives the world can be difficult and require extreme care.

October 15, 2012 | 01:20 PM - Posted by Mr. Old School (not verified)

I crossed my eyes but couldn't see it (same with the posters that used to be sold in the 90's), on the other hand I love the 3D effect on the 3DS and look forward to glasses-free 3D TV's coming down in price. Personally, I won't be upgrading my TV until they do. Until then all of the glasses based technology are useless to me since I wear prescription glasses that do not work well with them.

October 15, 2012 | 01:31 PM - Posted by Scott Michaud

Yeah it is not too easy or comfortable -- but is a reliable way to show full quality 3D especially on 2D monitors.

It does work a lot better if you click on the image and right-click/view image to view it full sized and without any border to distract you.

October 15, 2012 | 03:38 PM - Posted by Nilbog

Nice article.

I think you missed an important point.
3D just isn't done technology wise in the consumer space. Not so say it doesnt work, just not very well in the consumer space. Its dim, sometimes a little fuzzy, ect

I personally think we need to use IMAX as an example to how 3D should look. I have been to many 3D IMAX movies they always have fantastic quality, make good use of the 3D effect (stuff popping out of the screen), and it is crisp.
I'm no expert but i also think that we could use all of this leftover headroom while gaming to produce much better 3D games

October 15, 2012 | 06:01 PM - Posted by Scott Michaud

Thanks for the compliment!

It is not really about having things "pop out of the screen" except as a gimmick.

It is about giving our brains a more sharply defined object. When we want to make an object appear "crisper" we can see projections of relative angles between objects more precisely (increase resolution) and we can widen the gamut of colours we can perceive from it (vibrancy/contrast).

3D gives us another method: depth perception. We are now able to define the object in some spatial volume. That is a key factor for "quality" -- which is why the 3D images look crisper than either left or right image individually. The combined parallax is more information than either 2D image individually thus it looks crisper.

Most cases remove quality (or are just uncomfortable) in order to gain quality which is where my editorial comes from: if the combined 3D image is less crisp than the component 2D images then your 3D representation has only accomplished a gimmicky popping effect if it even accomplished that.

--------------

On the other hand I don't really have an IMAX or Dolby3D nearby me so my experience with it is limited. I have been to RealD theatres a few times though.

If you find that your theatre produces crisper images in 3D than they do in 2D -- then awesome. Whoever designed that theatre managed to cross over the "why bother?" threshold.

My (honestly very mild) concern is to make sure people understand that good 3D *should* produce a crisper image than a 2D image. Where it fails to do so is just that -- a failure to do so.

October 16, 2012 | 12:33 AM - Posted by Dream76 (not verified)

Once you train your eyes, you can start to look around the seen. very cool!!!

October 16, 2012 | 12:44 AM - Posted by Dream76 (not verified)

A faster way to get the image into 3D is to cross your eyes and you will start to see 3 images, start to focus on the middle image...

October 16, 2012 | 12:58 AM - Posted by Scott Michaud

Yeah but you need to be careful with that... people can strain themselves if they go for the goal too quickly.

October 16, 2012 | 06:45 AM - Posted by Reade B (not verified)

I used to be enthused about 3D because the IMAX theater near me looked great.

This was until I realized that there was a sweet-spot where you needed to sit in order avoid blurry double vision. Worse, I realized that the sweet-spot only worked for the center of screen and the sides were still blurry. This was supposed to 3D at its best.

I think when stereoscopic high resolution on-head(looks like a virtual 1080P display at the proper distance) displays that are comfortable and don't make you dizzy are at the right price point, 3D may have a revival.

Until then, I think 4K projectors and later 8K (or higher) wall displays are the technologies I'm looking out for.

October 16, 2012 | 09:48 AM - Posted by YTech (not verified)

Nice intro to the stereoscopic world.

To clarify the confusion which the industry is presenting, this technology is called Stereoscopic and not 3D (4D is totally incorrect). You are able to produce stereoscopic images from 2D and 3D images. 3D images are best to help define the depth of the object.

Thanks for the Unreal images. The effect did work for me, however, if only the images could have been much more detailed, the final product would not have been blurry.

I agree that you may strain your eyes if they are not trained or well develop for this technique. You could play around your everyday scenery (looking over a farm, sport field, etc) by trying to focus on a far distance object and then try to focus slowly on the blurred objects on the edges. If you receive any pain, look regularly at other objects around you; far and close. For office people who stare at monitors all day long, looking at far objects (preferably outside) will "help" relieve from eye-strain when practised on recommended intervals. (You should consult your optometrist for expert recommendations)

I would also like to add that in the 1950s, there were glasses that you could wear which used this approach of stereoscopic images. The photographer took two photograph at different angles and glued them to a board on a stick. The glasses allowed you to block outer distractions as you moved the image back and forth in the attempt to adjust the focal distance of the image to create a stereoscopic image.

As for the IMAX blurry experience, as being a technician for such high-end equipment, you will nothing such poor quality when the equipment as a whole has not been properly calibrated. Sadly, I've been noticing this issue throughout most public cinemas. Often it is because the staff who maintain the equipment are not well trained.

This technology in the public domain is still very young. As people do more trial, improved techniques will appear.

As for the 8k or greater resolution and detailed wall displays (televisions), they are being researched and we will start to see some impressive (and expensive) models come out soon (mid 2013). Some models are "almost" as crisp as looking through a sky-rise window.

Cheers :)

October 16, 2012 | 02:26 PM - Posted by Scott Michaud

Cheers! Thanks for the reply!

October 20, 2012 | 03:45 AM - Posted by PTB

I've been a fan of stereoscopic pics for a long time. In the old days they had two black squares above them to help you focus your eyes. You were supposed to stare at them until a third one appeared in the middle. When you saw three you were to focus on the middle one and then look down at the picture.

I found it best to look at them as if trying to look through the book. Like YTech mentioned " trying to focus on a far distance object and then try to focus slowly on the blurred objects on the edges".

My friend and I noticed that you could also cross your eyes and get a similar effect but the difference we noticed was when you crossed your eyes the 3d effect would be inward and when you did it the other way it was outward. For example say you have a picture of a cone (Mind you in those days the pictures were made out of black dots on a white page that resembled static on a T.V.) With the staring at the two black squares method the cone would be popping out at you and with the crossed eye method the cone would be tunneling into the page away from you.

For me the crossed eye method always hurt but was easier to achieve and hold onto than the other method. But the other method looked more crisp and I believe was the way the image was intended to be viewed.

February 3, 2013 | 09:54 AM - Posted by orvtrebor

I know this is an old article but I found it to be very informative.

I've been thinking about trying this out for games.

Sadly I couldn't get the sample pictures to focus (but I remember those posters from the 90's so I know I can do it lol).

May 1, 2013 | 01:17 PM - Posted by Eincrou (not verified)

Well done explaining that stereoscopic 3D viewing of content provides the brain with more information about the virtual scene it is viewing.

S3D is a complex subject, but the most important things for most people to understand are

1) ALL 3D cinema (yes, even Avatar and The Hobbit) are poor examples of stereoscopic content. They have to keep the depth mild so it's comfortably viewable for millions of people on many different screen sizes, resulting in unrealistic proportions. 3D cinema uses stereoscopy as a gimmick, though they are forced into it by the difficulty of unpredictable viewing conditions

2) Content is one issue, but the technologies used to view S3D content is another. There are many ways of producing the stereoscopic illusion. From anaglyph to polarized glasses to shutter glasses to autostereoscopic to cross-eyed and parallel viewing, each has benefits and drawbacks.

3) Currently, the ONLY place to get a truly awe-inspiring and genuinely immersion-aiding stereoscopic experience is gaming on PC. Stereoscopic drivers, such as Nvidia's 3D Vision or Tridef's 3D Ignition, give the user control of depth and convergence, allowing users to create a comfortable, yet deep and impactful, experience based on their own screen size, distance from the display, and personal preference.

3D films cannot predict these factors, and so they use a tiny amount of depth in an attempt to be one-size-fits all. PC gaming in S3D has no such limitation. 3D Vision 2 with a Lightboost monitor gives a bright, comfortable gaming experience.

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