3D is not without problems [Archive]

Markus Stone

02-11-2010, 03:17 PM

It's certainly an interesting article, but I'm not sure we're facing an epidemic of depthblindness. Head tracking VR is quite a different experience to watching something on a screen - there's much more orbital motion of the head involved, and therefore possibilities for just good old motion sickness to arise.

I imagine many people on this forum have seen Avatar - I'd be interested to hear if anyone experienced this effect afterward - but only AFTERWARD mind you. The thrust of the article is saying that when in the real world again, you will have difficulty resolving depth, leading to accidents.

The article doesn't say that nausea is part of the symptoms, btw which could be ascribed to the brain having issues with either bad 3D or the breakdown of accomodation and convergence (particulalrly if it occurred DURING the movie). This would be the exact opposite of the effect he is discussing, ie; the brain rejecting the 3D experience, rather than becoming so immersed it rejects the real world.

So - anyone become accident prone after seeing Avatar?

Cheers

-Markus

Eric Lange

02-12-2010, 06:49 AM

Marc Pesce article does touch on some cogent points even though they are crude or gross over simplifications.

I have worked with stereographic/Photogrammetric and immersive VR data sets and research for over twenty years. For stereo photogrammetric operators, there is substantial testing that is carried out to see if they can “take it” to work many hours a day in a stereo environment. The one thing I have found, is the exact opposite of what Marc Pesce states, is that instead of degrading or ruining people’s stereo acuity, in fact working with “good” stereographic data sets actually improves your ability to handle progressively more challenging ranges of parallax.

The issues and psycho-visual break down occur mainly with incompatible view accommodation versus convergence. I.e. your eye balls swivel in their sockets to converge on an apparent point, but the depth of the point is out of the plane of the view screen that the lenses in the eyeball is used to focusing too. The viewer has to learn to dissociate a particular focusing distance with a particular vergence angle of the eye balls. It’s basically a learnt skill that improves over time.

I think the other thing that causes headaches (which is something that people don’t talk about), is that in nature, when your eyes converge on a point that point is in focus, (for example your thumb at arms length), the back ground will be perceived as a double image, and anything in front of your thumb will also be a double image. The things in the background and foreground are also blurred due to lack of focus (as you are fixing your gaze on your thumb). The stereo visual system is heavily reliant on correspondence matching between left and right images, that have a high frequency content, (i.e. contrasty fine texture and edges). The parts of the perceived image that are out of focus are essentially blurred (i.e. low frequency features), and not rigorously “pattern matched”, never the less the unresolved stereo percept (even as a double image) has a rough depth associated with it. By stark contrast, in the movie theatre, everything is in focus at one plane, and what happens is that your brain is forced to process about twenty times the normal volume of stereo matchable data than it normally would, (as compared to what the system was evolved to do to essentially serve the Paleolithic caveman bumbling around the woods in France, looking for snails and boars to eat). The brain is quite happy to stereo resolve many millions of stereo corresponding points per second, in a sort of stereo spatial gluttony, but after a while, basic channels and bandwidth in the brain DO GET TIRED! [The associated neurons do get wrung out like a sponge of all their dopamine etc.]. By analogy, you can do difficult calculus for a couple of hours, but fifteen hours straight and your brain juices for that capability get totally used up.

I totally agree that sufficient testing has not been carried out to set up various safety guidelines. I am particularly sensitive stereo fatigue myself and yet I have engineers who can work with horrible data sets with their eyeball out on stalks for half the day. However we have a set of technologies that allow one to completely resample stereographic data sources into very comfortable ranges of viewing parallax and still preserve very fine 3d details, so it looks very rich and engaging, (something not possible via conventional techniques). This also allows one to shoot successfully with much wider base separations/IOD. These techniques work especially well for real time environments such as games. This came about as an accidental industrial by product for new computational and spatial paradigms we were researching to vastly improve the computational efficiency of capturing and rendering very complex geometries and real world scenes for stereographic and VR applications. The user (of a 3d TV) can also be given a controller (using our techniques) to in effect dial up or dial down the range of parallax (not just simple HIT). So all of these kinds of problems are cleanly fixable, in a practical way.

Stereo 3d is definitely not going away (now), and if there are class action law suits, bring it on, (our US patent was recently granted), we have technologies to take care of these problems. The question is now, is industry willing to take these types of stereo-physiological issues seriously or will things just bumble on as they are? I personally think the competitive market will decide, and the punters will buy systems and media that have the capability to present themselves in a more stereo comfortable and flexible way. I.e. people like their stereo but they want to control how much stereo effect that they want at a given time, understanding that (like doing math) they can’t push it fifteen hours a day, but at least they are warned that they should take responsibility for how much “parallax” they ingest. It’s a bit like putting a warning on a case of Doughnuts, [Do not eat these doughnuts continuously for fifteen hours straight, every day of your life], all though there will be the occasional “Twinkie” defense in the stereo market place and associated law suits, never the less If extra controls and parallax re-sampling are offered to the user, then it is the user’s responsibility to decide how much parallax they want at any given moment. This is the way forward I believe.

Cheers,
Eric

Michael Rintoul

02-12-2010, 07:21 AM

People have been looking at stereo images for over 150 years,.... Are there any cases of stereo blindness as a direct result??? Perhaps the problems arise when you try to move your tv to within one inch of your eye as in the VR headset... try to focus on the dirt on your sunglasses for a couple of hours and then see how you feel.... Not to mention that almost all of the depth sense cues are maintained in 3-D image capture (perspective, occlusion, atmospheric perspective, light gradient, textural gradient, motion parallax, degree of focus...etc) This article is narrowly researched and parallels are draw to 3-D without any merit at all....

Eric Lange

02-12-2010, 07:48 AM

There are numerous problems with head mounted displays, but there are optics that allow your eyes to focus to a notional distance for example three feet into the distance. The problem here is that your eyes are forced to focus to that distance, and a dissociation of view accommodation with convergence becomes especially difficult (as compared to 3d tv/monitors). There are many patents out there for HMDs that attempt to change focus in the lenses to actually and physically match view accommodation with convergence. Other techniques try to pattern match some parts of the scene to automatically effect a horizontal image translation to effect a zero parallax condition at the notional point of convergence for the eyes. These systems are fraught with many problems, and are really not that much fun for home use (at least not right now).

As Michael says stereo has been around 150 years, (actually much longer than that for hand drawn examples), but at the same time we must challenge ourselves all the time to create high quality stereo and strive for technical solutions to some of these very real problems. If we ignore these issues, people will get fed up, and stereo will die. But I believe in the relevant industries, that a second wave of products and solutions should take care of things in a fairly substantial and coherent way.

Cheers,

Eric

Foot note:

“Keep doing that you’ll go blind” as the title of the article, is an oblique reference to the Victorian belief that if you masturbate too much you will go blind… and yet stereo was all the rage in the 1880’s,? The Victorians didn’t have much to say about what happens if you use (Victorian) stereographic porn; do you go blind twice as fast? This is a bit tongue in cheek, the article was written by an Aussie I guess with a good sense of humor (from the title of the article). It is an absolute certainty that there will be law suits and ambulance chasers, but it won’t sink an industry and will of course create new opportunities. From my experience working with large VR displays for larger audiences, etc. about one in a hundred and fifty people will have real problems with stereo that lasts for a couple of days, this is a fact that cannot and must not be ignored.

Dan Hudgins

02-12-2010, 09:21 AM

There is a serious and major problem with stereo content and screen size.

You CANNOT display the same formated data on the "big screen" and a home TV since on a home TV or computer monitor the distance for points that look at INF would be 65mm and 65mm on a 1000mm wide screen is,

65/1000 or 0.065 the image width.

But if you show that same formated 3D images on a IMAX screen 20,000mm wide the ratio is not the same,

65/20000 or 0.00323

Unlike 2D images that scale to any size screen, the 3D images must be formatted to "fit" the screen size that will be used so that points for subjects at INF have a spacing of 65mm.

If you view formated (65mm) for a 12" monitor (width) then view on a 36" monitor without adjusting the "offset" of the stereo pair you get 65mm * 36/12 =195mm which would make your eyes diverge for INF, something your eyes shoud NEVER do! It gets much worse if you project on a big screen,

65mm* 200000/(12*25.4) = 4265mm

Even though the screen is not as close as the 12" monitor would be and eye spacing (spacing for points at INF) of 4265mm will always make the viewers eyes diverge, and is worse for people who sit close to the screen.

The only solution for using data formated in the same way on different size screens is to set INF at the screen plane so there is 0 disparity for INF and then the eyes can only converge and never diverge.

Otherwise the "stereo" window needs to be smaller than the monitor screen so you can slide the two images around to compensate for the viewing distance and screen size.

For monitoring you should use VR glasses rather than a monitor, or a viewing hood on the monitor rather than glasses.

Eric Lange

02-12-2010, 09:38 AM

Brent J. Craig

02-12-2010, 09:52 AM

That article makes no sense. The author says that the wikipedia page for 'depth perception' lists 10 different cues that your brain uses to figure out exactly how far away something is, but fails to mention that 3D films use at least 8 of these cues as well!

He author thinks head-mounted immersive VR headsets are the same as watching a movie, and he talks about red/blue anaglyph glasses as if they are commonly used.

Where did he come up with the line "None of the television manufacturers have done any health & safety testing around this."? That's a pretty bold statement to make without any facts to back it up. Did he convince every TV manufacturer to reveal the trade secrets of how or if they test their sets? Bullsh**!

Certainly 3D can be done badly, just like anything else, but done properly by trained professionals it is an amazing experience.

Dan Hudgins

02-12-2010, 10:05 AM

Dan, using conventional technologies I agree with you.

However there are ways around this, and at least with the technologies we have developed allow one to effectively re-sample the scene real time to new ranges of parallax to suit and optimize for virtually all screen sizes, but 3d rendering capability does need to be in the pipeline, for example a games console or a dedicated (not too substantial) rendering engine for cinematic applications. The sequences can also be re-rendered off line and then stored for play back if necessary. The data sets have to be pre-processed but after that the adjustments can be made real time.

Cheers,

Eric

I decribed something like that in the 80's but it is not 3D photography once you start relocating the pixels, and you need to resolve the hidden parts.

Also without a standard viewing method, you cannot know in post how the end viewer will see your images, having the viewing device re-format the images is like letting the viewing device re-grade your images, what then is the maker making?

Cardboarding from using compressed imaged in DI and projection makes the 3D value less, because the beauty of 3D in the the fine 3D texture that gets lost with compression that was desigined for 2D images. 3D requires more resolution in each image not less.

I solved the "missing" 3D depth clues issues years ago in some papers I published on how to make "hologram" like video displays with accomidation depth clue and motion parallax in all three axis, that were published by the SPIE in their proceedings, so his blanket statement that there are no ways to resolve the isues is not Comprehensive.

Eric Lange

02-12-2010, 10:23 AM

Dan,

Read US patent 7643,025 B2, ...

www.uspto.gov/web/patents/patog/week01/OG/html/1350-1/US07643025-20100105.html

to see if you can get it/understand. The application was dumbed down substantially in the hope that the examiner’s might get it. I think then you will get a better idea as to what the user vs the data preparator can sensibly accomplish (excellent question I think you pose), and how “card-boarding” is essentially cured (in the scenario you imagine).

Have fun, the specification is 54 pages long, but I think you might be able to understand/dig it.

Cheers,
Eric

Alex G. Cohn

03-12-2010, 04:07 PM

I think the only way to get true "3D" that approximates the way that the human eye actually sees would be to have variable focus content, where the system tracks your eyes and changes the focus to the object at which you are looking.

But I'm not sure how that would work with video.

icester

03-14-2010, 07:48 AM

Leonard Coster

03-15-2010, 01:06 AM

Hey Guys,

On the divergence limits - there are two.
Background is the one causing the discussion here.

In the real world you see distant objects with your eye lines parallel - about 65mm apart if you're an average Human.
When we present these images in the the cinema we ideally want to place infinitely distant backgrounds 65mm apart so the audiences eyes are parallel when observing them.
But we do NOT want them more than 65mm apart ever because this is asking the audiences eyes to point outwards and the do not like this at all!

You therefore need to limit the background divergence in your images to 65mm on the largest screen it will ever be shown on.

Doesn't this limit the experience on smaller screens?
well.... yes and no.
On smaller screens the background divergence will be a smaller number of actual mm for sure but as a percentage of the field of view it is exactly the same and the illusion still works.
Remember this is all an illusion!
Also since a small screens tends to occupy a smaller fraction of your field of view than when you are sitting in a cinema, your brain compensates and you see a proportional degree of depth.

Try this experiment on a 3D monitor - this works in anaglyph or any screen technology - play a scene and then back away from the monitor - across the room - down the hall - you'll see that the 3D scene appears to get DEEPER as you back away.

Smoke and mirrors :-)

What I do is shoot for the big screen and let the smaller ones take care of themselves. This produces natural low eye strain footage that I know will work anywhere and actually looks good.

There's a terminology and initial discussion on this on my site www.speedwedge.com
I'll be publishing more there soon - feedback is welcome.

Markus Stone

03-16-2010, 05:30 PM

I agree with you on the theory, but in practical real world terms, pretty much every 3D film out there stretches this limit a bit. Most people's eyes can diverge by as much as 2 degrees without causing too much discomfort, and most productions take advantage of this fact (yes, even avatar) because there is an area between where the eyes start to diverge and before everyone starts going all Marty Feldman.

As an example, on my computer monitor, I can theoretically have objects with 64mm worth of background parallax, but this equates to 13% of the screen width. This delivers images that are difficult to fuse at the edges because only 74% of backgrounds overlap in any two images.

On the other hand, with a larger screen (lets call it 22m) 64mm equates to 0.3% of screen width, which makes for a pretty underwhelming 3D effect, even on such a big screen.

Most shows I've worked on and seen are in the realm of 1 - 1.5% of screen width, which asks the audience to diverge between 0.4 and 0.7 degrees on a 22m screen, which is quite comfortable for most people and delivers far more depth. It's worth testing in a cinema. It's suprising how far these limits can be pushed and still create fusable images. I found that on a 15m screen I could quite happily fuse out to 3% BG parallax, which is a divergence of 1.5 degrees on a front row of 7m. Of course, I wouldn't advise actually using 3%, just trying to illustrate that the eyes can and do diverge in small amounts quite happily. It's just a matter of balancing comfort and depth.

Cheers

-Markus

Leonard Coster

03-17-2010, 12:18 AM

Hey Markus,

Yes of course you can exceed these limits if you want to. No one will stop you.

It's a matter of degree and duration as well. Including how long you give people to accommodate a shift in convergence before cutting to the next scene and how far you expect them to adjust across that cut.

There is also a distribution of accommodation limits across the population just as there is a range of colour perceptions - from the fully colour blind to full colour viewers.

In general if you stay within the safe limits you can make pleasing stereoscopic footage which won't hurt anyone.

There is no law about this!
It is a subjective limit to be discussed between your stereographer and director.
These tools are there to support the narrative. Sometimes you will want a very shallow stereo effect, other times you want to maximise the effect.

All I would say on that is that if you exceed comfortable limits and the illusion begins to break then you are not maximising the effect, rather destroying it. You know your stuff though and how to work to the chosen delivery format. There is a large range of personal taste in this as well as the mathematical limits i have discussed above. It is a guide to where the limits are, that is all.

Cheers!

icester

03-17-2010, 10:13 AM

Hey Guys,

On the divergence limits - there are two.
Background is the one causing the discussion here.

In the real world you see distant objects with your eye lines parallel - about 65mm apart if you're an average Human.
When we present these images in the the cinema we ideally want to place infinitely distant backgrounds 65mm apart so the audiences eyes are parallel when observing them.
But we do NOT want them more than 65mm apart ever because this is asking the audiences eyes to point outwards and the do not like this at all!

You therefore need to limit the background divergence in your images to 65mm on the largest screen it will ever be shown on.

Doesn't this limit the experience on smaller screens?
well.... yes and no.
On smaller screens the background divergence will be a smaller number of actual mm for sure but as a percentage of the field of view it is exactly the same and the illusion still works.
Remember this is all an illusion!
Also since a small screens tends to occupy a smaller fraction of your field of view than when you are sitting in a cinema, your brain compensates and you see a proportional degree of depth.

Try this experiment on a 3D monitor - this works in anaglyph or any screen technology - play a scene and then back away from the monitor - across the room - down the hall - you'll see that the 3D scene appears to get DEEPER as you back away.

Smoke and mirrors :-)

What I do is shoot for the big screen and let the smaller ones take care of themselves. This produces natural low eye strain footage that I know will work anywhere and actually looks good.

There's a terminology and initial discussion on this on my site www.speedwedge.com (http://www.speedwedge.com)
I'll be publishing more there soon - feedback is welcome.

That is completely false.
If you do that the background that should be at infinity will end-up few inches past the screen and all action would have to be in negative parallax or you have to make the stereo window floating 2 meters away from the front raw.

65 mm 5 deg projected at 10 m is 873.2 mm

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Leonard Coster

03-17-2010, 02:22 PM

icester

03-22-2010, 07:14 AM

Hi Mathew,

Harsh words man - I think we may disagree on that one...

If the BG divergence is at my eye spacing - say 65mm - my eyes are parallel when observing it and that creates the illusion of those objects being at infinity.

My point is that these offsets - in screen mm will be smaller on a smaller screen but that there is an interesting optical illusion - which I have observed - that helps maintain a degree of perceived depth in the scene despite this.
I thought it was interesting enough to discuss here.

I do believe you need to take the actual background image offset, as delivered on the biggest final screen, into account or you could end up with large offsets - as your example shows.
That requires the audiences eyes to turn substantially outward to resolve the image which I personally avoid doing to my viewers as i believe it produces unnecessary strain.

There are many different styles of shooting - 3D will be no different.

Happy converging !
Wrong again..
The "65 mm 5 deg projected at 10 m is 873.2 mm"
is always the same regardless of screen size.
Also if you are referring to all wrong projection geometries as styles then you shopuld call it pseudo-S3d styles.
For a human viewer sitting in font of a screen of given distance and size there is only one stereo geometry which must deliver realistic viewer experience of the real world.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Eric Lange

03-22-2010, 09:06 AM

icester

03-22-2010, 01:10 PM

Hello Everybody.

Mathew, do you have a ray diagram of what you are talking about here?
There perhaps seems to be a little confusion about what is being discussed, and I don’t think we/everybody are all on the same page here.

Cheers,

Eric

It is the positive parallax limit@human.stereo.vision.geometry.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Eric Lange

03-22-2010, 04:37 PM

I think I agree with a little of what everybody is saying here. Both Leonard and Mathew on different points.

5 degrees angular screen distance is a bit much for me, I can do 4, at five I cannot fuse. At ten meters viewing distance, the two corresponding stereo points can be placed at 870mm apart on the screen (just as Mathew says); in my case closer to 700 mm. I think people forget that eyes/lenses are angular devices and focal length of the eye is a factor as well as the angles of convergence by which eyes can be expected to swivel by in their sockets (to fix their gaze upon a single point). I.e. Objects or specified widths appear smaller the further away you place them…

The scene from Father Ted when he explains to Dougal about cows and perspective.

Not posted on RED stereo forum for the first time (I might add)!

www.youtube.com/watch?v=98hO97ky-sA

I like Leonard’s point in that if you can make it work on the big screen, then it is probably going to work for the small screen, but not necessarily the other way round. The reason for this, ( I believe) is that when you work stereoscopically on a monitor you sit nearly two feet away from it. That’s the angular equivalent of almost sitting behind the back row in a cinema. The front row could be like putting your face six inches away from the monitor. Therefore if it works for the front row in a cinema then it’s probably going to work SAFELY on a monitor or home display, even though it may err on the side of weaker or less dramatic/boring looking stereo. ). I get the point about the stereo “stretching” out to meet you.

I think people need to be more mindful of the total range of parallax (angular or otherwise) that is in a given scene that we can be expected to “ingest” without fusion problems and conflicts/pain and headaches. It’s all very well to talk about BG parallaxes, but what you put “infront” of that is just as responsible if not more so for the headache you are going to get.

I don’t know how many minutes of sustained AGULAR divergence people can take and to what degree (pun intended)?

Cheers,

Eric

Leonard Coster

03-22-2010, 09:55 PM

Wrong again..
The "65 mm 5 deg projected at 10 m is 873.2 mm"
is always the same regardless of screen size.
Also if you are referring to all wrong projection geometries as styles then you shopuld call it pseudo-S3d styles.
For a human viewer sitting in font of a screen of given distance and size there is only one stereo geometry which must deliver realistic viewer experience of the real world.

Mathew Orman

Hi icester,

Sorry I think you're missing my point.
We are not necessarily able, or even trying to replicate exact natural vision in the cinema.
Often you use different focal lengths, frame rates, filters, all sorts of techniques. There are technical and subjective reasons for this.

My point is that I still want to deliver images that are within the normal ocular accommodation range of the viewer.

You will not necessarily produce a stereo illusion that matches actually being at the film location for the viewer but you will still be delivering a stereoscopic image.

To me, this means keeping the stereo coherent so that your audience is immersed ie not breaking the illusion - which makes the effect less, not more - and not causing brain strain so they can't enjoy the show or have to leave.

I understand the distinction between an accurate stereo reproduction of an environment and one where the stereo geometry is not strictly real world accurate.

Given the many other objectives or limitations on set I would argue that it is not always possible to present a strictly accurate image without making those images very difficult to accommodate (fuse) for the viewer.
In those circumstances, or for other subjective reasons, we may choose to deviate from strict dimensional accuracy of reproduction.

Otherwise we should also ban all lenses that are not standard FoV - also ban off speed shooting etc etc.

All my discussions of background & overall divergence limits are aimed at keeping the stereo image within the range that can be easily accommodated by the audience.

If your aim is to accurately reproduce the dimensionality of the location then this becomes the driving factor in your setups. It will determine your choice of focal length and IOD.
This will limit the range of distances from camera for your subjects and/or where you place the convergence point - but you can achieve it.

I hope I've explained myself clearly - please describe your objectives in case I have misunderstood them.
Whatever they are I'm sure they are achievable - as with everything there is often a compromise but we're used to that in film making :-)

Eric Lange

03-23-2010, 07:01 AM

Following on a bit from what Leonard said; there does seem to be this “belief” that for good stereo you MUST replicate exactly the human IOD (inter ocular distance), but I have to say, if you do this you end up very with un-engaging stereo for many different types of scenes and circumstances. The Victorians did this with their stereoscopes, and cardboarding and lack of 3d complexity in fine detail was the norm. In fields such as Stereo Photogrammetry (terrestrial and Ariel), good photogrammetrists have been able to push things to the max to squeeze out every last drop of 3d texture out of a recorded subject through the use of very low distortion wide angle lenses, large formats and surprisingly wide base separations (or IODs,( which think is a misnomer)).With experience and knowledge it is possible to create absolutely spell binding stereograms. Distortion correction and judicious alignment and re-sampling can go a long way to create detailed and engaging stereograms, WITHOUT divergence, or Y parallax from distortion, or ranges of parallax and nonsensical horizontal image translations. From a simple point of view one might say that we aim to capture and generate for the viewer the richest 3d percept we can, without carelessly pushing the limits too far (just like what Leonard is saying).

Reconstruction of natural geometry does not allow you to do this. Just in the same way we shoot 2d movies we don’t aim to replicate the same visual experience that a human would have (same format and focal length and angle of vision); if you did this for a whole movie, it would be interesting for a few minutes, but largely un-artful and ridiculous. The notion of replicating “natural” geometry is even more pointless in the case of stereo as it is just as artificial as a 2d movie, by virtue of the fact that it is all projected onto a flat screen. A biological binocular convergent system (the nuts and bolts of human stereopsis) cannot perform “naturally” in this environment; no way no how.

The flat screen really changes the game from nature. If you hold out your thumb you can converge and fix on that point. Objects in the distance are stereo un-fused as blurry double images, but never the less the brain is aware roughly what relative distance these unresolved blurry double images are. If you place your other hand six inches away from your face and fixate still on the thumb at arm’s length the blurry double image of the hand six inches from your face does not conflict with the fused images of your thumb. You cannot do this in a cinematic environment because everything is composed of sharp imagery presented at a single distance on a flat plane. Therefore ALL of the imagery presented on screen has to be SIMULATANOUSLY stereo resolvable/fusable by the human visual system. Therefore the range of parallax presented on screen as compared to nature MUST be very much smaller. It is (I belive) the stereographer’s art to eek out the maximum effect from this narrower range of parallax while staying within comfortable and safe viewing limits. However, I also believe that the human brain is not used to “ingesting” large parallel volumes of broad field stereo fusable data, and this also results in basic “brain tiredness” beyond simple psychovisual mismatches, as in nature you would never normally process the same gigantic volumes of stereo fusable data.

I have to say YES pay attention to safe and comfortable viewing parameters, but “natural geometry” is ALMOST meaningless when set against the artificial constraint of a large flat screen.

Ta

Eric

PS. I don’t think anyone seriously trying to argue that stereo ray geometries that are not “natural” should be called “pseudo –S3d” is going to get very far with that idea and terminology, as “natural” geometry does not really exist when you have a flat screen; unless of course you are displaying a stereogram of a coplanar flat screen (on a flat screen)! It also means that 99.999% of stereo cinematic shots would have to be called Pseudo S-3d, which frankly is not very practical. “Toy Story 3, now in Disney Pseudo 3d, or Psuedo-not quite Real-D”…

In photogrammetry a “ Pseudo-stereogram” is one where the left and right images are swapped to produce an inverted Z of the scene. I think Icester may be referring to that in the context of a 65 mm on screen BG parallax?

icester

03-23-2010, 09:49 AM

Hi icester,

Sorry I think you're missing my point.
We are not necessarily able, or even trying to replicate exact natural vision in the cinema.
Often you use different focal lengths, frame rates, filters, all sorts of techniques. There are technical and subjective reasons for this.

My point is that I still want to deliver images that are within the normal ocular accommodation range of the viewer.

You will not necessarily produce a stereo illusion that matches actually being at the film location for the viewer but you will still be delivering a stereoscopic image.

To me, this means keeping the stereo coherent so that your audience is immersed ie not breaking the illusion - which makes the effect less, not more - and not causing brain strain so they can't enjoy the show or have to leave.

I understand the distinction between an accurate stereo reproduction of an environment and one where the stereo geometry is not strictly real world accurate.

Given the many other objectives or limitations on set I would argue that it is not always possible to present a strictly accurate image without making those images very difficult to accommodate (fuse) for the viewer.
In those circumstances, or for other subjective reasons, we may choose to deviate from strict dimensional accuracy of reproduction.

Otherwise we should also ban all lenses that are not standard FoV - also ban off speed shooting etc etc.

All my discussions of background & overall divergence limits are aimed at keeping the stereo image within the range that can be easily accommodated by the audience.

If your aim is to accurately reproduce the dimensionality of the location then this becomes the driving factor in your setups. It will determine your choice of focal length and IOD.
This will limit the range of distances from camera for your subjects and/or where you place the convergence point - but you can achieve it.

I hope I've explained myself clearly - please describe your objectives in case I have misunderstood them.
Whatever they are I'm sure they are achievable - as with everything there is often a compromise but we're used to that in film making :-)

At current level of achievements in the field of image acquisition and projection there are many technological solution that can deliver virtual world experience with full rage of human stereo-vision accommodation.
In the next few years the S3D technology will prove that
state of the art geometrically correct methods deliver
experience that is so real that it would be hard to believe that it is only virtual.

What you are proposing is showing a chank of the space placed at distance where it does not strain the eyes of the viewers and flattened enough to allow for wide rage of viewer distances regardless of distortions in scale and perspective.
I call that pseudo-stereo and the only problem in S3D is just that: forcing viewers to watch pseudo-stereo will produce bad psychological and physical results regardless of how small and easy it is to fuse it.
Mismatches in FOV, scale, inertia, acceleration, camera dynamics, specular effects, etc. result in tonally confused viewer experience.

Just in AVATAR one character was shown in so many different scales but none with 1:1 and the impression was just a confusion because if you show a character 10 times smaller then his motion inertia indicate as if he was made out of lead. In next scene the same character is 10 times larger so now the impression is as if he was made out of Styrofoam.
Another gross mismatch was re-texturing of CG characters and compositing. The textures all look as stained paper with zero stereoscopic specular effects resulting in dull look just like all 2D to 3D cheep conversion.
Those are just two of to many mismatches that ware placed in AVATAR by it's creators.
Billboards may work well in 3D but is S3D they look just that: plain flat. Human stereo vision is a precise measurement and navigation instrument and cannot be fulled by 2D tricks. Real life specular textures can only be reproduce in S3D in 3d they just all look like color stains
on matte paper.
If bad S3D like AVATAR is worth millions then perfect
S3D will be worth much more.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

icester

03-23-2010, 09:58 AM

Eric

PS. I don’t think anyone seriously trying to argue that stereo ray geometries that are not “natural” should be called “pseudo –S3d” is going to get very far with that idea and terminology, as “natural” geometry does not really exist when you have a flat screen; unless of course you are displaying a stereogram of a coplanar flat screen (on a flat screen)! It also means that 99.999% of stereo cinematic shots would have to be called Pseudo S-3d, which frankly is not very practical. “Toy Story 3, now in Disney Pseudo 3d, or Psuedo-not quite Real-D”…

In photogrammetry a “ Pseudo-stereogram” is one where the left and right images are swapped to produce an inverted Z of the scene. I think Icester may be referring to that in the context of a 65 mm on screen BG parallax?

Yes, because you would not want to be called pseudo-stereographer.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Eric Lange

03-23-2010, 10:26 AM

Yes, because you would not want to be called pseudo-stereographer.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

That's quite funny;

So I guess that would make Lenny Lipton (for example) a Psuedo-Stereographer as well. Given that I design and build very advanced digital stereo photogrammetric workstations and software aswell as very high end VR apps, I would LOVE to be called a “PSUEDO-STEREOGRAPHER”. I think that’s great. Thank you Icester!

May I recommend the book “How to Win Friends and Influence People?” by Dale Carnegie; Amazon has it for $7.99, might be a worthwhile investment.

www.amazon.com/How-Win-Friends-Influence-People/dp/0671723650

Mathew, just as a foot note we use stereo texturing just in the way you are asking for, a critical eye just as you describe is useful, but also realize that people also seek help on the Forum and it certainly pays to listen. The stuff posted by Pedro on the Synch issue with RedOne is absolutely priceless. Many tens of thousands of dollars could be spent to perform the same tests to get the same valuable information. That's why folks are keen to be fairly supportive at every opportunity as there is something you can certainly learn from everybody, whether or not they have their math right or not, it seems in a lot of cases they are at least DOING it right, and anyone making the case for less extreme stereo (in psychovisual terms), and without seeming patronizing, should be commended and encouraged [as in Leonard's case]!

icester

03-23-2010, 11:53 AM

That's quite funny;

So I guess that would make Lenny Lipton (for example) a Psuedo-Stereographer as well. !

Wow, that is a perfect score.
If you want to know why, ask Michael Starks he will
tell you who or what is Lenny Lipton under the skin.
Or you might want to research what happened to TEK 3D technology by TEKTRONIX.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Eric Lange

03-23-2010, 12:36 PM

Wow, that is a perfect score.
If you want to know why, ask Michael Starks he will
tell you who or what is Lenny Lipton under the skin.
Or you might want to research what happened to TEK 3D technology by TEKTRONIX.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Icester man, you crack me up; (seriously, I am beaming from ear to ear ( Cheshire cat move over)).

How much gasoline do you want to throw on this one? I am based in New Mexico, maybe I can score some U235 from Los Alamos for you? I guess in the interests of professional decorum, one is not at liberty to ask for such details (no matter how interesting), and things start to cross a line that should never appear in print (especially in a post), but feel free to PM me any pertinent information that you FEEL might warrant a little further investigation in the matter (for the blissfully ignorant), that would not legally constitute slander. Nobody is really going out of their way to deliberately create enemies, but from a technical standpoint perhaps, therefore I guess you would also regard Michael Starks as a well meaning pseudo-stereographer as well?

Sounds like someone has a nice collection of axes to grind; perhaps this is akin to stereo-therapy for angry embittered “true” stereographers.

Where do you go from here (I am laughing) though....?

[Sincerely, thanks for the laugh]

Eric

( I should really ACTUALLY do some work I’ll check in later :beer:);

icester

03-23-2010, 02:19 PM

Icester man, you crack me up; (seriously, I am beaming from ear to ear ( Cheshire cat move over)).

How much gasoline do you want to throw on this one? I am based in New Mexico, maybe I can score some U235 from Los Alamos for you? I guess in the interests of professional decorum, one is not at liberty to ask for such details (no matter how interesting), and things start to cross a line that should never appear in print (especially in a post), but feel free to PM me any pertinent information that you FEEL might warrant a little further investigation in the matter (for the blissfully ignorant), that would not legally constitute slander. Nobody is really going out of their way to deliberately create enemies, but from a technical standpoint perhaps, therefore I guess you would also regard Michael Starks as a well meaning pseudo-stereographer as well?

Sounds like someone has a nice collection of axes to grind; perhaps this is akin to stereo-therapy for angry embittered “true” stereographers.

Where do you go from here (I am laughing) though....?

[Sincerely, thanks for the laugh]

Eric

( I should really ACTUALLY do some work I’ll check in later :beer:);

Yes, you are right I will email you directly with attached PDFs that Michael Starks had just sent me.

Getting back on REDUSER relevant subject: I am developing FULL HD stereoscopic adapter for a single RED ONE camera with normal stereo base, off-axis lens geometry and stereo-window adjustable from 1m to infinity. Should have a prototype soon and will post samples hopefully in new S3D blue/ray format.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Leonard Coster

03-23-2010, 08:35 PM

Leonard Coster

03-23-2010, 08:42 PM

Icester !

I would love to see some of your footage - soon as you can post any of it please lets have a look.
I have my own 3D monitors and projection so even if you just have left/right eye as eg quicktime I can play that.
Otherwise I can wait for your to present it in whatever forum you prefer.

Cheers,

Eric Lange

03-24-2010, 07:29 AM

Thanks for jumping in there Eric... very brave of you :-)

Hey will you be at NAB? I'm giving a talk there on Tuesday afternoon 2:30 post pit.
I'd love to discuss your work also - VR stations have been into Stereo vision for a lot longer than mainstream projection.

Maybe see you in April.

Cheers,

I really should stop being lazy and reclusive, and go to NAB, would be cool to see you and your talk, maybe I bring a box to plug in so you can see what all the fuss is about.

Cheers

Eric

Eric Lange

03-24-2010, 07:35 AM

Yes, you are right I will email you directly with attached PDFs that Michael Starks had just sent me.

Getting back on REDUSER relevant subject: I am developing FULL HD stereoscopic adapter for a single RED ONE camera with normal stereo base, off-axis lens geometry and stereo-window adjustable from 1m to infinity. Should have a prototype soon and will post samples hopefully in new S3D blue/ray format.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Hi Mathew,

Thanks for the info, I can discuss with you off list, need some time to digest these tomes. Today is my B-day so I’ll have some fun rather than drench myself with the woes of the “3D industry”; Starks seem like an interesting guy and his work is well known in the patent literature.

So perhaps your sentiments and the title of the thread are particularly apt.

“3D IS NOT WITHOUT PROBLEMS!”

Cheers,

Eric

:emote_hippie:

icester

03-24-2010, 08:28 AM

Hi Mathew,

Thanks for the info, I can discuss with you off list, need some time to digest these tomes. Today is my B-day so I’ll have some fun rather than drench myself with the woes of the “3D industry”; Starks seem like an interesting guy and his work is well known in the patent literature.

So perhaps your sentiments and the title of the thread are particularly apt.

“3D IS NOT WITHOUT PROBLEMS!”

Cheers,

Eric

:emote_hippie:

Happy Birthday!
Hope you shoot some 3D for keeps...

All the best,

Mathew Orman

icester

03-26-2010, 01:42 PM

Dan,

Read US patent 7643,025 B2, ...

www.uspto.gov/web/patents/patog/week01/OG/html/1350-1/US07643025-20100105.html (http://www.uspto.gov/web/patents/patog/week01/OG/html/1350-1/US07643025-20100105.html)

to see if you can get it/understand. The application was dumbed down substantially in the hope that the examiner’s might get it. I think then you will get a better idea as to what the user vs the data preparator can sensibly accomplish (excellent question I think you pose), and how “card-boarding” is essentially cured (in the scenario you imagine).

Have fun, the specification is 54 pages long, but I think you might be able to understand/dig it.

Cheers,
Eric

There is a slight problem with that.
The algorithm that does 3d reconstruction from stereo pair will fail on specular reflection, refraction and transparencies. It will only work good on paper textures with ambient lighting.
So then you end-up with some false depth and your intend to reduce parallax by nonlinear or perspective modification of 3D volume will insert new distortion
which ware not present in original stereo pair.
Phillips WOWvx had gone bust because of their attempt to normalize the depth volume to get comforable fixed
range parallax.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

icester

03-26-2010, 01:51 PM

I think the other thing that causes headaches (which is something that people don’t talk about), is that in nature, when your eyes converge on a point that point is in focus, (for example your thumb at arms length), the back ground will be perceived as a double image, and anything in front of your thumb will also be a double image. The things in the background and foreground are also blurred due to lack of focus (as you are fixing your gaze on your thumb).
Cheers,
Eric

Not quite,
human eye are different than fixed geometry lens.
When you focus on horizon the thumb in front of your nose is out of focus, but when you focus on your thumb
all background including horizon is in perfect focus.
Check it out...
Also, there is nothing wrong with blurred vision, I am 51 and I use +1 diopter glasses for foreground world but I can
take them off and not use it and will never get any headaches or discomfort.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Eric Lange

03-26-2010, 03:41 PM

There is a slight problem with that.
The algorithm that does 3d reconstruction from stereo pair will fail on specular reflection, refraction and transparencies. It will only work good on paper textures with ambient lighting.
So then you end-up with some false depth and your intend to reduce parallax by nonlinear or perspective modification of 3D volume will insert new distortion
which ware not present in original stereo pair.
Phillips WOWvx had gone bust because of their attempt to normalize the depth volume to get comforable fixed
range parallax.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

The interface that we have, probably has one of the best manual editing interfaces for stereo immersive feature extraction, and in essence you introduce the more advanced automated algorithms within that context. It has always been my view that such an interface would always live or die by the quality of its manual editing features, simply as right now machine vision is nowhere near as good as the stereo acuity or visual interpretive capability of the human visual system, (but we are working on new automated approaches that are best suited to producing coherently stereo textured models).

The use of stereo textures in the paradigm of coherently stereo textured models in fact embeds specular reflections, refraction and transparencies (as you describe) into the model as it is able to re-present to the respective left and right eyes what you would naturally see (nothing is thrown out!). Therefore a very sparse number of points only needs to be extracted, as a polygonal substrate is used as a framework to support the stereo textures. A judicious selection of these points is required rather than the blanket extraction of many millions of very noisy points. In most instances the polygonal substrate is the basic shape of the object/scene, but the stereo textures are mapped using a network of tri-homologous points. The eye/brain defer to the disposition of the stereo textures in true 3d space once the whole scene is essentially re-rendered as a stereogram. The basic method was originally designed to find a way to accurately record and re-present historic and archeological sites in true 3d/VR systems, (as part of PhD I did at Cambridge University (in the UK) some years ago). The basic problem with historic sites is that you have fantastically rich and complex surfaces over a very wide area that have to be represented in a computationally efficient way and also be metrologically accurate (to less than 1 mm over an entire site). Standard laser scanning and standard photogrammetric 3d automated extraction techniques, and associated data have very real intractable mathematical problems. Therefore I came up with the CSTM which is conservatively 400 times more efficient at representing complex surfaces over conventional explicitly modeled surfaces. It also had the accidental (industrial) byproduct that it allows one to re-render a scene to safer ranges of parallax from a wide IOD WITHOUT compressing the fine 3d textures. The main aspect of the system is designed to join together many stereoscopically captured images to allow one to construct much larger models for example, a whole film set or an ancient cathedral ruin. The interface and software has also been designed to handle multiple camera positions for 360 degree dynamic scene acquisition.

Because the polygonal substrate in true 3d space is essentially invisible to the viewer very few stereo corresponded points are required compared to conventional “auto-extraction” methods. The auto extraction algorithms we are developing are very picky in the sense they have what can best described as a heightened sense of “garbage suppression” as only a small number of points are actually required.

Standard algorithms as you indicate do have real problems, but when you are using CSTMs it’s a new frontier, and new approaches have to be used from the ground up. The technique produces very clean models that support terrific complexity in a computationally very efficient way (in other words things look extremely life like, and you can get away (visually) with murder).

As you can imagine there are many applications.

Thanks for the Question.

Eric

Eric Lange

03-26-2010, 03:52 PM

Not quite,
human eye are different than fixed geometry lens.
When you focus on horizon the thumb in front of your nose is out of focus, but when you focus on your thumb
all background including horizon is in perfect focus.
Check it out...
Also, there is nothing wrong with blurred vision, I am 51 and I use +1 diopter glasses for foreground world but I can
take them off and not use it and will never get any headaches or discomfort.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

You must be a lucky man or have really long arms. I certainly can’t do that and I have very good eye sight, I guess everybody is a bit different, or maybe I'm becoming a bit short sighted spending too much time at a computer terminal posting on red 3d forum!.

icester

03-26-2010, 04:32 PM

The interface that we have, probably has one of the best manual editing interfaces for stereo immersive feature extraction, and in essence you introduce the more advanced automated algorithms within that context. It has always been my view that such an interface would always live or die by the quality of its manual editing features, simply as right now machine vision is nowhere near as good as the stereo acuity or visual interpretive capability of the human visual system, (but we are working on new automated approaches that are best suited to producing coherently stereo textured models).

The use of stereo textures in the paradigm of coherently stereo textured models in fact embeds specular reflections, refraction and transparencies (as you describe) into the model as it is able to re-present to the respective left and right eyes what you would naturally see (nothing is thrown out!). Therefore a very sparse number of points only needs to be extracted, as a polygonal substrate is used as a framework to support the stereo textures. A judicious selection of these points is required rather than the blanket extraction of many millions of very noisy points. In most instances the polygonal substrate is the basic shape of the object/scene, but the stereo textures are mapped using a network of tri-homologous points. The eye/brain defer to the disposition of the stereo textures in true 3d space once the whole scene is essentially re-rendered as a stereogram. The basic method was originally designed to find a way to accurately record and re-present historic and archeological sites in true 3d/VR systems, (as part of PhD I did at Cambridge University (in the UK) some years ago). The basic problem with historic sites is that you have fantastically rich and complex surfaces over a very wide area that have to be represented in a computationally efficient way and also be metrologically accurate. Standard laser scanning and standard photogrammetric 3d automated extraction techniques, and associated data have very real intractable mathematical problems. Therefore I came up with the CSTM which is conservatively 400 times more efficient at representing complex surfaces over conventional explicitly modeled surfaces. It also had the accidental (industrial) byproduct that it allows one to re-render a scene to safer ranges of parallax from a wide IOD WITHOUT compressing the fine 3d textures. The main aspect of the system is designed to join together many stereoscopically captured images to allow one to construct much larger models for example, a whole film set or an ancient cathedral ruin. The interface and software has also been designed to handle multiple camera positions for 360 degree dynamic scene acquisition.

Because the polygonal substrate in true 3d space is essentially invisible to the viewer very few stereo corresponded points are required compared to conventional “auto-extraction” methods. The auto extraction algorithms we are developing are very picky in the sense they have what can best described as a heightened sense of “garbage suppression” as only a small number of points are actually required.

Standard algorithms as you indicate do have real problems, but when you are using CSTMs it’s a new frontier, and new approaches have to be used from the ground up. The technique produces very clean models that support terrific complexity in a computationally very efficient way (in other words things look extremely life like, and you can get away (visually) with murder).

As you can imagine there are many applications.

Thanks for the Question.

Eric
Epilinear geometry supports arbitrary camera position in a scene but still fails on lighting effects regardless of the algorithm used. The ruins are mostly covered with dull specular textures and any 3d reconstruction method woks fine on it. Also such structures
are not in human everyday vision menu so if there are errors and or artifacts the human brain will most likely ignore it or assume as normal shapes of damaged structure.
There is no problem to apply stereoscopic texture on a model, but how do you get correct model from stereo pair in the first step. Also if you do that with CG models then the lighting geometry will conflict with specular effects in stereoscopic textures.
I guess the example with original plus normalized parallax would be a prove that your concept works.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

icester

03-26-2010, 04:35 PM

You must be a lucky man or have really long arms. I certainly can’t do that and I have very good eye sight, I guess everybody is a bit different, or maybe I'm becoming a bit short sighted spending too much time at a computer terminal posting on red 3d forum!.
If you have very good site then why are you saying that it is not possible to focus on a thumb finger that you hold in front of your nose. I am sure that almost anybody in the World can do that.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Eric Lange

03-26-2010, 06:58 PM

Epilinear geometry supports arbitrary camera position in a scene but still fails on lighting effects regardless of the algorithm used. The ruins are mostly covered with dull specular textures and any 3d reconstruction method woks fine on it. Also such structures
are not in human everyday vision menu so if there are errors and or artifacts the human brain will most likely ignore it or assume as normal shapes of damaged structure.
There is no problem to apply stereoscopic texture on a model, but how do you get correct model from stereo pair in the first step. Also if you do that with CG models then the lighting geometry will conflict with specular effects in stereoscopic textures.
I guess the example with original plus normalized parallax would be a prove that your concept works.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

When you see it you’ll get it. You are making extrapolations about technology that you don’t YET understand, and have not seen. But probably in the not too distant future you certainly will, probably on both counts. No big deal really. But I think you'll like it becuse it puts most of the things you are, or have been "complaining" about to bed. If you don't like it after that, then I doubt there will be much to please you at all (my good man!).

Eric Lange

03-26-2010, 07:15 PM

If you have very good site then why are you saying that it is not possible to focus on a thumb finger that you hold in front of your nose. I am sure that almost anybody in the World can do that.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

As far as the thumb thing goes, I was of course referring to your statement:

”When you focus on horizon the thumb in front of your nose is out of focus, but when you focus on your thumb all background including horizon is in perfect focus….Check it out…” [ICESTER]

That is, a thumb held out at arms length, and one fixes one’s gaze upon that, that you claim that you can simultaneously see the background horizon also in sharp focus at the same time. I was saying I cannot do that i.e. simultaneously perceive a sharp infinity focus while focusing and converging on my thumb held at arms length (even in bright sun light) all at the same time. That was the technical point that you were trying to make?

Interestingly I find if I close one eye and look at my thumb then the horizon is sharper, but with binocular fusion, fixing my gaze on the thumb, the background is pretty blurry. It maybe that your natural diopter is equivalent to a “hyperfocal” distance for the human eye perhaps, I really don’t know.
I am sure that there are loads people reading this thread that would love to chime in on this….

In the mean time, roger, over and out.:emote_popcorn:

icester

03-27-2010, 04:31 AM

As far as the thumb thing goes, I was of course referring to your statement:

”When you focus on horizon the thumb in front of your nose is out of focus, but when you focus on your thumb all background including horizon is in perfect focus….Check it out…” [ICESTER]

That is, a thumb held out at arms length, and one fixes one’s gaze upon that, that you claim that you can simultaneously see the background horizon also in sharp focus at the same time. I was saying I cannot do that i.e. simultaneously perceive a sharp infinity focus while focusing and converging on my thumb held at arms length (even in bright sun light) all at the same time. That was the technical point that you were trying to make?

Interestingly I find if I close one eye and look at my thumb then the horizon is sharper, but with binocular fusion, fixing my gaze on the thumb, the background is pretty blurry. It maybe that your natural diopter is equivalent to a “hyperfocal” distance for the human eye perhaps, I really don’t know.
I am sure that there are loads people reading this thread that would love to chime in on this….

In the mean time, roger, over and out.:emote_popcorn:

Cross-eye viewing is also a prove that when you focus on imaginary cross-point the images on the screen are in perfect focus regardless of the screen distance.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

Eric Lange

03-27-2010, 06:03 AM

Cross-eye viewing is also a prove that when you focus on imaginary cross-point the images on the screen are in perfect focus regardless of the screen distance.

Mathew Orman

For state of the art stereoscopic vision systems with: eyestrain free, distortion free and realistic immersion stereoscopic experience contact me
at:
http://www.tyrell-innovations-usa.com/

??????

Eric Lange

03-27-2010, 06:47 AM

Mathew you still crack me up;

Are you sure you don’t own a bear that you drive around in an ice cream van?

OK just to help you out and perhaps re-frame the discussion to something interesting and useful. I think some of the points you raise, (all be it in a rather abstract and abrupt fashion, are indeed interesting).

Looking at some of the other threads you have posted on including this one, (it seems), your main plank is that EVERYBODY must use “natural geometry”. I and others put forward the idea that “Natural Geometry “ in a cinematic environment is a nice idea but not practical or desirable. The main argument I put forward is that “natural geometry” is not really possible when you are projecting onto a flat screen (for large ranges of parallax and corresponding distances). I and many others on the lists here believe that nice and engaging stereographic presentations are the goal, that are also safe, pain free and do not push the limits. The other point I put forward is that because one uses a large flat screen, that a narrower range of parallax has to be used compared to the range of parallax the human visual system would naturally handle when viewing the real world. One of the main reasons for this, is if you present the same much wider ranges of parallax on screen then this means that there will be parts of the imagery that will be un-fusable, and hence cause very uncomfortable eyestrain and headaches. I think it’s a really bad idea to put stereo imagery that has stereo corresponding features that the audience cannot resolve within the context of other elements that they can (i.e. painfull double images in the forground or back ground). With natural binocular convergent viewing in the real world with real 3d objects disposed at various distances, then unresolved stereo images (for example in the back ground, are not a problem (as previously discussed)). Herein lies the difference between stereo viewing of real objects in a real 3d world vs. stereo viewing on a large flat screen. Not to mention the very basic and well known conflicts that a flat screen can cause in terms of view accomodation vs convergnece. The only %100 cure for that is a volumetric screen/space in an essentially holographic environment.

This does therefore raise the question whether shooting scenes with a very shallow depth of field (but not using a long lens) produces acceptable back ground blurrs? I.e. what degree of blurriness can be induced until the human visual system does not want to stereo fuse or sense a conflict. I.e. with controlled uniform back grounds these do not interfere with the foreground subject (from a parallax point of view), but I wonder what degree of blurred backgrounds with some vague features at infinity you can get away with. I think this is the real killer for most good stereo, a foreground subject with backgrounds that go to infinity (or are at least hard to deal with).

Mathew I would offer you the opportunity to set down “on paper” i.e. on this list, what exactly ARE the specifications and criteria that YOU suggest MUST be used for stereo cinematography and “natural stereo geometry”. If you set these down as a clear list of requirements, then I think we can start to understand what it is that you are essentially pressing for or demanding. As it may be, that what you are essentially asking for may already be employed to some degree by what you would describe as “pseudo stereographers”. A set of specs and criteria would bring real focus to the discussion. If it’s solid and unique we can call it the Orman Condition.

Very Best,

Eric

P.S. Just as a hint (Mathew), I think one of the things you may be driving towards is to use convergent camera geometry, rather than parallel. In photogrammetry convergent camera geometry is routinely used (for decades), but the backgrounds HAVE to be controlled. Unresolvable crossed over backgrounds with large parallaxes on a flat screen are not cool for comfortable cinematic viewing, but I guess it all depends on what you are doing, and HOW you are doing it! It's that damned flat screen again! I don't think lateral keystoning (from convergent camera geometry) should be a problem if you crop in but I'm sure others would dissagree.