Stereoptic Images

[David]

Hi All - I'm not sure where this should be posted, but I reckon this section will do. I've been playing around with creating 3D or stereoptic images. Here are a couple of examples. The effect can be quite spectacular.



The basic idea is to take two shots a few inches apart. Close-up shots like this require a separation of about 1 - 2 inches, whereas distance shots need about 2.5 inches, the average separation between the eyes. To view the images, look at them from about 1 metre away and cross your eyes. The 3D version pops out. Most people can do this with a bit of practice. I learnt over 40 years ago when studying undergraduate chemistry. Stereoptic images of molecular structures were all the rage.



This second shot involved taking 5 shots at each of the two positions and then combining them with Combine ZP to achieve a good depth of focus.

Comments and crits welcome as usual.

Cheers

David

[robphoto]

Hi David

Will take your word for it as I would prefer to keep the eyes 'uncrossed' for now!! Avatar has fulffiled my 3D requirements for now!

[cneedha]

I still have my freshman chemistry text from 1979- just broke it out this fall from the storage box as my daughter is taking chemistry. It has a 'steriopticon' for looking at molecules! Works reasonably well on your photos
Chris

[David]

Hi Chris - I remember those devices as well. However, as I recall (but it may have been different in US), the stereoptic images were arranged for "wall-eyed" viewing (ghastly terms I know), i.e. the image taken on the left was put on the left and the image taken on the right was put on the right so that the left eye looked at the left side etc. The images in my examples are arranged so the left shot is on the right of the combined image etc. This is the "cross-eyed" view. Without a stereopticon, using a "cross-eyed" method is easier. However, even the "cross-eyed" arrangement can be successfully viewed with the stereopticon or similar device as the brain appears to compensate. It is quite an eerie thought that what you and I take as obvious 3D in real life is a construct of our brains.

Thanks for your interest and I hope your daughter does well in her chemistry.

Cheers

David

[will_c]

Well this certainly works! I'm not sure that I'd want to look at it for too long, but it's a striking effect.

[timo2]

That works great, good job David!


Try crossing your eyes on this image to see what is revealed:

[rpcrowe]

Overlappping aerial reconaissance images.

We used to use a stereo viewer which would allow us to view sequential vertical aerial prints in pseudo three dimension.

Some photo interpreters could make out 3-d imagery by crossing their eyes but, I never could. I needed the stereo viewer.

I was with the U.S. Navy's Light Photographic Squadron 62 during the low level photo reconaissance of the Russian Missiles in Cuba in October 1962. Those missiles really popped out to me when I looked at the prints with the viewer...

[David]

Hi Tim - I know this type of image as an anaglyph - and I'm hopeless at them! I can see a "3D" shape, coming down from the top left and along the bottom and another part in the top right but that's it. I think there are two reasons why I find these very difficult. First, I do not know what it is I am supposed to be seeing. The thing with stereograms from photos is that you know what the object is. When I say "you" I mean your brain knows. So-called 3D information is a construct of the brain, not of your eyes. Thus, the more the brain knows about what it is looking at the more easily it can construct a meaningful image. Second, anaglyphs almost always construct an image in "negative" space, i.e what is perceived is what is not there with respect to the pattern.Again, the brain (at least mine) has a problem with that. If I know what I'm meant to be seeing I can usually visualise it after a while, then it becomes easy.

Richard - what an interesting history! What a thing to know someone who was in the front line, so to speak, of the Cuban Missile Crisis when I was a schoolboy and the country was preparing for imminent nuclear war. We were all given instructions about what to do, where to go, how to store water and foodstuffs. I remember sitting in class one day, after JFK had issued the US ultimatum to Kruschev, wondering if there was really going to be a war. The whole class was subdued and the teacher (Jock Mearns, French) was very tight lipped. Scary times.

Here are two links for 3D images:

http://www.yorku.ca/eye/toc-sub.htm

and

http://http://www.stereoscopy.com/downloads/

Happy Days

David

Update: My best guess is that it is a whale with its tail to the LHS and going up, and what I thought was a cloud is spray from a blow-hole.

[Donald]

Richard - what an interesting history! What a thing to know someone who was in the front line, so to speak, of the Cuban Missile Crisis

For all the young people who are wondering what 'Cold War' and 'Cuban Missile Crisis' is about, an excellent scholarly, but accessible, text is John Lewis Gaddis', 'The Cold War', Penguin/Allen Lane, 2005. Gaddis is Lovett Professor of History at Yale and has been described at 'the dean of cold war historians'.

In a gripping way he shows us, as David comments upon, just how close we were in 1962.

[David]

Donald - I've just added your book reference to my wish list on Amazon. You are absolutely correct about 1962. Younger people have no idea of what went on. I've just been sitting in a dwam for the last few minutes thinking about what might have occurred and comparing that to the petty whinings of politicians and pundits these days. I'll have to stop or I'll go into Rant Mode

David

[timo2]

Hi David. When I took that anaglyph image to be framed, there were two shop assistants at the counter, one said, ‘nice abstract’. I said it wasn’t an abstract and explained how to view it to see the image it contained. They both looked again and one of them suddenly said, ‘oh yes, I can see the ***** and the **** ****’. The other one stared harder and harder and ended up swearing there was nothing there and that we were both winding her up.

Lots of people have looked at the original, some can see it, some can’t. One thing I find that can sometimes help people break through and see it is, if they move their head slowly a few inches side to side while going crossed eyed because the 3D image then moves and pops out. Also, if they can see their own reflection in the image (the computer screen or frame glass), and focus on that, that can help too because the focal distance to see the 3D image is twice the distance it’s being viewed from.

[Donald]

Hi David. When I took that anaglyph image to be framed, there were two shop assistants at the counter, one said, ‘nice abstract’. I said it wasn’t an abstract and explained how to view it to see the image it contained.

That is indeed amazing. I didn't think it would work on a computer screen (don't know why). Once you do see it, then it comes back easily the next time. As you say David, the brain is then tuned in to know what to look for.

Usually I have no problem getting the 3D effect from images such as you have presented David. However, am struggling with these. will keep staring.

[rpcrowe]

David,
You wrote...
"Richard - what an interesting history! What a thing to know someone who was in the front line, so to speak, of the Cuban Missile Crisis when I was a schoolboy and the country was preparing for imminent nuclear war. We were all given instructions about what to do, where to go, how to store water and foodstuffs. I remember sitting in class one day, after JFK had issued the US ultimatum to Kruschev, wondering if there was really going to be a war. The whole class was subdued and the teacher (Jock Mearns, French) was very tight lipped. Scary times."
This probably isn't quite the place to venture back on memory lane but, I really haven't thought about those days in October 1962 when the world was on the brink of nuclear war...
I will post some remberances, since they are photographically related, in the common room...

[David]

Hi Tim - I was both wrong and right about your stereogram. As I could not work out what you could see, I googled my way to some useful sites and found out that I do see these in negative space - a hole where you see a structure. By applying the nose to the surface technique I can now also see what the stereograms wish you to see. There was still a problem with your image as I could not hold the "3D" view for more than a second or two. So I copied the image and squared it up using the perspective tool in the Gimp. That gave a much better view of the **** and the **** ****. I'm still not 100% sure that I really know what it is but the bit on the top RHS sure looks like a thing that floats around so to speak, while the larger structure, in the words of Dr McCoy might be" a ****, Jim, but not as we know it."

Cheers

David

[timo2]

Well, it’s been there a while so I’ll say what it is: On the left, it’s the space shuttle Discovery with its loading doors open and nose pointing down to the bottom middle of the picture. Behind and to the right is a Saturn like planet with a ring around it and top right, a satellite.

I think I see what you mean about negative space now David, the picture does recede into a space behind the frame.

[David]

Tim - So I got the space ship and satellite correct, but I'm not sure about the planet.

The negative space is not so much to do with recession or depth in the image but to do with the shape of "objects" in the image. This is quite a complicated stereogram in that there are several objects in it. If you look at some of the simpler ones such as the shark that pops up (pun intended) on most "magic eye" sites, the effect, literally as I see it, may be more apparent. The shark appears as a 3D hole - no detail, just a hole with the general shape of the shark. Actually, I have never found reference to this effect on any site, and I always assumed that what I saw was what I was meant to see, but now I know differently.

It's all very weird, the way we perceive images.

Cheers

David

[mastamak]

Hi All - I'm not sure where this should be posted, but I reckon this section will do. I've been playing around with creating 3D or stereoptic images. Here are a couple of examples. The effect can be quite spectacular.



The basic idea is to take two shots a few inches apart. Close-up shots like this require a separation of about 1 - 2 inches, whereas distance shots need about 2.5 inches, the average separation between the eyes. To view the images, look at them from about 1 metre away and cross your eyes. The 3D version pops out. Most people can do this with a bit of practice. I learnt over 40 years ago when studying undergraduate chemistry. Stereoptic images of molecular structures were all the rage.



This second shot involved taking 5 shots at each of the two positions and then combining them with Combine ZP to achieve a good depth of focus.

Comments and crits welcome as usual.

Cheers

David

David,
I likewise learnt to view images stereoscopically (as we called it) while studying to be a surveyor. To view the photographs stereoscopically you have to force each eye to to view each individual image. That is the right eye has to be focused on the right image and vice versa for the left eye. It is quite easy to do by simply relaxing the eyes and allow them to stare into the distance without focusing on any individual image. When you do this the eyes will be focussed parallel to each other and the images will appear to pull together into one and you can see the three dimensional effect. Photogrammetrists do this to view stereoscopic aerial photographs to make maps but they use a stereoscope which is essentially two magnifying glasses mounted on a steel frame which constrain the eyes to view in parallel. You can do it without the stereoscope but it is a bit tiring on the eyes. It is also much easier if you arrange the images so that like points are about 6.5cm apart - that is, the distance between each eyeball. The further apart the images the greater the stereoscopic effect but the harder it is to view the images because instead of the two eyes having to view parallel to each other they have to diverge and this is very unnatural. The reduced size images above are much closer and thus easier to view. You can also view by forcing your eyes crosseyed, as you have mentioned by holding your finger halfway between your eyes and the image and focussing on that, but I always found that a bit wierd. The effect is due to the lateral displacement (x-axis) of like parts in each image. Good images by the way.
Grant

[David]

Grant - Good summary of the procedures. I use the cross-eye technique whereby the right eye image is on the left and vice versa. I happen to find that easier for my perception, but the parallel method is just as good. I reckon that if you had two movie cameras set about 2 - 3 inches apart and played their recordings back on parallel screens then people like me who can see without a stereoscope should be able to see the resulting images in 3D. If someone gives me a second Canon 5D Mark II then I'll try the experiment.

Cheers

David

[timo2]

Tim - So I got the space ship and satellite correct, but I'm not sure about the planet.

The negative space is not so much to do with recession or depth in the image but to do with the shape of "objects" in the image. This is quite a complicated stereogram in that there are several objects in it. If you look at some of the simpler ones such as the shark that pops up (pun intended) on most "magic eye" sites, the effect, literally as I see it, may be more apparent. The shark appears as a 3D hole - no detail, just a hole with the general shape of the shark. Actually, I have never found reference to this effect on any site, and I always assumed that what I saw was what I was meant to see, but now I know differently.

It's all very weird, the way we perceive images.

Cheers

David

Perception eh, just a small easy subject reality, like time, is a peculiar concept I have some difficulty with too

Since you mentioned it, I went looking for shark ones… I like this one:

[pono]

I never could see anything in these images. I had one on my wall when I was a kid. My head hurt for two days after an hour long session trying to figure out. These things can be very hazardous. I'm jealous of everyone who can figure them out.