8 ms·

Cross Views

173 points by moultano 2y ago

StevenNunez 2y ago
Jokes on you! I can only see from one eye at a time!
- fffrantz 2y ago
  Yep, same here. Discovered I was stereoblind quite late as well as I thought it was the norm and my brain just got used to it.
tombert 2y ago
I love this effect. I had a book of Magic Eye pictures as a kid, which was a similar effect. I'm not sure how practical the "crossing your eyes to get 3D" thing actually is, it makes my eyes water after a minute or so, but it's still sort of cool to see my cheapy monitor doing 3D without any special glasses.
- tomw1808 2y ago
  I had the same book - the one with the black border? :) There was a dolphin or something, right? So long ago, can barely remember... The water eye thing only happens to me if I cross my eyes and focus before the picture and not behind the picture. The latter takes some time to let the eyes relax, but its much more natural.
- RIMR 2y ago
  If you stitch the photos together seamlessly, you can display them on a VR headset in a really natural way. I take stereo images in landscape mode, stitch them together top/bottom, and then enjoy them on my Quest 2 using the Pigasus media player. If you use a 180° fisheye lens, you can immerse yourself in the scene. just make sure to keep the camera perfectly level, or you'll end up making yourself sick if you try to view the images unadjusted.
- voytec 2y ago
  "Wow, a sailboat!"
- regularfry 2y ago
  I seem to recall that Magic Eye pictures had you decross your eyes, so you were looking past the page. It was a bit harder to do.
- alnwlsn 2y ago
  I only learned somewhat recently that a lot of (or all?) Magic Eyes are meant to be parallel viewed instead of cross eyed. The difference was pretty impressive the first time I saw one correctly.
- vrighter 2y ago
  eh, you get used to it. I've watched whole movies like this
nashashmi 2y ago
I want to know why cannot the multiple cameras on my phone be used to create 3D images.
- tomw1808 2y ago
  They can, or? Apple calls that spatial videos, or does that work differently?
  - Philpax 2y ago
    Yes, the spatial videos that iPhones can record are just stereoscopic video. This hasn't been cloned by other manufacturers because there have been very few viewing devices that they own, but that might change with Android XR.
- dist-epoch 2y ago
  Because they are not the same focal length? Although I'm sure software can mitigate that to some extent.
- regularfry 2y ago
  They're not far enough apart. Stereo vision on humans is best inside 3-5 metres, usually, and by 10 metres out is not that great. That's with pupils 65mm apart, give or take. Now scale that down to the horizontal distance between lenses on a phone. Coincidentally on mine they are about 13mm apart. You just multiply everything down linearly: my camera has the same experience at 60mm distance from an object as I do at 3m. It would be pretty useless past 2m, but also with those constraints you'd notice the quality drop off with range within a single object that was approaching 50cm depth. Now that's OK itself, you could get some useful work done with that, but there are so many provisos to it that it would be very hard to sell as a feature. To top that off it's algorithmically painful. There's a reason the commercial 3D scanners don't (typically, only) use stereo pairs; there's almost always a better way to do it.
  - regularfry 2y ago
    (oh, and to get out ahead of questions: Spatial Video capture on the iphone 15 apparently uses the LIDAR sensor for the depth map, not just the cameras)
deadbabe 2y ago
I thought this would be about wigglegrams
Kerbonut 2y ago
Is it just me or do they have some of the left/right images swapped?
- throw310822 2y ago
  Came to say the same. Depth is inverted for me. Is it because instead of looking at each picture with the eyes straight, we cross them (and each sees the opposite picture)?
  - moultano 2y ago
    If they look inverted you are probably diverging your eyes instead of crossing them. In that case the images in this section should look correct. https://moultano.wordpress.com/2025/02/24/you-should-make-cross-views/#:~:text=If%20you%20are%20able%20to%20diverge%20your%20eyes%20instead%20of%20crossing%20them%2C%20then%20arranging%20the%20images%20the%20opposite%20way%20can%20give%20you%20a%20more%20relaxing%20and%20more%20natural%20stereo%20effect.%20This%20corresponds%20to%20focusing%20past%20the%20image%20instead%20of%20in%20front%20of%20it. https://moultano.wordpress.com/2025/02/24/you-should-make-cr...
    - foobarian 2y ago
      Heh I thought you must've tested these on a teeny tiny monitor to make them work. No wonder! But of course when crossing eyes there is essentially no limit. Thanks for the clarification.
- moultano 2y ago
  I just went back and doubled checked, and they're all correct. If they look inverted, you are probably diverging your eyes ("parallel view") instead of crossing them. If that's more comfortable for you there is a section of images arranged with that orientation at the end of the article.
- dragonwriter 2y ago
  The first set are (as the text says) designed for cross-eyed viewing, the others for parallel. These use opposite left/right arrangement. So if it feels like half of them are backwards, you are maybe using the same viewing method for both sets?
zehaeva 2y ago
Ugh, there's some people out there who cannot see these. Not for a lack of trying, I've personally been trying since the 90s.
- wkat4242 2y ago
  It took me a while too. Especially those double images that look totally contorted and only come out when you relax your focus. It took ages but suddenly they popped and now i can do them every time. Once they came through they were crystal clear.
- kookster310 2y ago
  The trick for me was to completely cross my eyes and produce the double images, then slowly uncross/cross them until I could start to see the image, which eventually clears up.
- stewarts 2y ago
  I am with you. I could also never see the hidden image things. Been trying for 40 years.
- dist-epoch 2y ago
  Do you manage to align the two small white squares above each picture so they are on top of each other?
  - moultano 2y ago
    Yes.
- tantalor 2y ago
  There are two communities, you need to find out which one you belong to. https://www.reddit.com/r/CrossView https://www.reddit.com/r/CrossView https://www.reddit.com/r/ParallelView https://www.reddit.com/r/ParallelView There is a test image you can try: https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fg5ilwgk99r781.jpg https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fg... Whichever "view" looks to be closer is the one you should use.
EvanAnderson 2y ago
I've done this with my SLR. Moving the camera different amounts can give a more pronounced effect, however it can be more difficult to get the image to converge. I had a lot of fun with doing this 20 years ago. Sadly, my visual acuity has become significantly different between my eyes (even w/ correction) and the enjoyment of 3D displays has really diminished as as result. Just musing because I'm working and busy: I wonder how difficult it would be to do video. (Obviously you'd have to shoot two videos in parallel versus just moving the camera and shooting again.) Converting existing 3D videos to a cross-eyed viewing format would probably be the easiest way to experiment with it. I wonder if anybody has done that. I've never looked at 3D movie formats before. I always assumed it was two interleaved streams.
- wkat4242 2y ago
  You should move it by the distance of your pupils for the best effect. Mine is bog standard 63mm so I'm lucky. If you get it wrong things will look too big or too small and the 3D effect will be softer or too pronounced.
  - llm_trw 2y ago
    The point is that you can force the respective of a giant or an ant if you so choose. Using two cameras I had a time lapse of a fog coming in where you could see the 3d structure becuase they were at two different streets looking out. Like op this was done nearly 20 years ago. Now you don't even get fog any more.
    - Jarmsy 2y ago
      I remember reading about a physical device someone constructed with mirrors (I think at an early burning man) that gave you the experience of a huge inter ocular distance to get a giant's eye view. I've always wanted to try one (or the opposite to experience a tiny inter ocular distance).
      - Jarmsy 2y ago
Karawebnetwork 2y ago
When they wrote "your screen can display 3D photos", I thought it would be a hardware hack and not something that depends on a human physiology hack. Something like stereoscopic GIFs come to mind, e.g. https://tenor.com/fr-CA/view/dain-stereoscopic-daingifs-3d-monster-gif-9119977 https://tenor.com/fr-CA/view/dain-stereoscopic-daingifs-3d-m... In other words, taking the two images and swapping them quickly creates the illusion of depth. Edit: Looking into it, there's a word for it. Wiggle stereoscopy: https://en.wikipedia.org/wiki/Wiggle_stereoscopy https://en.wikipedia.org/wiki/Wiggle_stereoscopy
- zro 2y ago
  There's a whole bunch of these over at https://old.reddit.com/r/wigglegrams/ https://old.reddit.com/r/wigglegrams/ if you want more
stronglikedan 2y ago
> Your screen can display 3D photos. That's a stretch, but I guess clickbait is required to get engagement nowadays.
- moultano 2y ago
  As long as you don't regret the click, I don't regret baiting the click. :)
- ellenhp 2y ago
  > nowadays People have been writing provocative titles for things since before the internet.
thih9 2y ago
I prefer wigglegrams. If you're looking for an example - Wikipedia page has one from 1927[1]! [1]: https://en.wikipedia.org/wiki/Wiggle_stereoscopy https://en.wikipedia.org/wiki/Wiggle_stereoscopy
- blululu 2y ago
  Was going to say the same thing. Presenting stereo pairs has a lot of layout and resolution issues to say nothing of the fact that some people have stereo blindness to varying degrees (lazy eye is an extreme case). The author is correct that stereo depth can greatly enhance an image, but a wigglegram does this at full resolution with no visual puzzle solving.
- ilyagr 2y ago
  Thank you! I have not, to this day, have been able to see any Magic Eye/Cross Eyed or similar images. A wigglegram is immediately trivial. I'd probably most appreciate a layout with one frame on the left, the wigglegram in the middle, and the other frame on the right, so that I can get a sense of both the distances and the detail.
- James_K 2y ago
  I'm slightly suspicious that this comment was written by a bird.
- dagss 2y ago
  WHAT... this is the first time in my life I have been able to see 3D with one eye! Closing one eye and I still see the depth effect. Main brain works very differently than I assumed... With this effect I guess one could make even people who are blind on one eye see in 3D
haunter 2y ago
Nintendo 3DS gang rise up! Though it wasn't perfect or useful that much it was still a nice feature, made some fun photos with it.
ben7799 2y ago
I can generally see the Magic Eye pictures very well.. these are way harder. The tiny thumbnails at the bottom of the page work, but the larger images I can't cross my eyes enough. I think it depends greatly on getting the screen/image size just the right size and also getting the viewing distance right. On large monitors it seems harder to see.
- on_the_train 2y ago
  I believe the author switched left and right. Because the inverse ones at the bottom work fine
  - moultano 2y ago
    Magic eye pictures are viewed by diverging your eyes, so the "parallel view" versions at the bottom work correctly with that method. "Cross view" pictures require converging your eyes, so the images have to be in the opposite position from what your eye would see.
    - ben7799 2y ago
      You're right.. guess I always thought Magic Eye was converged. Once I look at the ones at the bottom and just zoom in/out in the browser I can see them perfectly. I have a 33" monitor and seeing them means sitting much closer than normal and then zooming out in the browser.
    - deleted 2y ago
      [deleted]
    - on_the_train 2y ago
      Nah, magic eye is crossing, at least the ones I know. And I can only do crossing
- moultano 2y ago
  Yes, making them smaller certainly helps.
- 2y ago
colingauvin 2y ago
This is very common in structural biology papers, where you need to make figure of complex 3D arrangements of atoms, but the figures must be printed in 2D. Typically using molecular modeling software, you find your view of choice. Then you rotate +- 0.5° and render two images, and put those side by side as a stereo pair figure. It takes quite a bit of practice to see them well: https://spdbv.unil.ch/TheMolecularLevel/0Help/StereoView.html https://spdbv.unil.ch/TheMolecularLevel/0Help/StereoView.htm...
- regularfry 2y ago
  I did this on a school project back in the 90's, with a structure of quinol clathrate that was completely wrong but very pretty. I was very into povray at the time. My chemistry teacher didn't quite know what to make of it...
- BrandoElFollito 2y ago
  Thanks for that! It is quite impressive and I learned to see the 3D molecule on first try. I remember seeing something similar, but made of an array of dots (you did not know what was behind the doors until you see it by crossing your eyes)
- groggo 2y ago
  technically rotation is going to end up giving a slightly different result than lateral displacement, right? but it's very similar for small distances.
dandsupernig 2y ago
[flagged]
throwaway494932 2y ago
The video game Magic Carpet had a couple of 3D modes, anaglyph 3d requiring blue/red classes, and stereogram mode [1]. The latter was not really usable, but it was a cool trick, expecially for the time ('94). [1] https://youtu.be/iZT-S2F191I?si=8k9jniqA98wgq0Hu&t=1090 https://youtu.be/iZT-S2F191I?si=8k9jniqA98wgq0Hu&t=1090
- vrighter 2y ago
  i once found a renderer for quake 2 that rendered in stereograms. Managed to make it through the first level
lopatamd 2y ago
[dead]
rahimnathwani 2y ago
most stereograms are designed to look correct when you cross your eyes This is how I look at stereograms (looking nearer than the page), but at least some of the images on this page seem like they're designed for the other way around (looking in the distance, beyond the page). This one looks weird when I look at it cross eyed, but fine when I look at the other way. https://moultano.wordpress.com/wp-content/uploads/2025/02/17405320419888595852203168102922.jpg https://moultano.wordpress.com/wp-content/uploads/2025/02/17...
- moultano 2y ago
  Yes, the ones at the bottom, in the "Parallel View" section are designed to be viewed the other way.
  - rahimnathwani 2y ago
    Sorry, I stopped reading part way and was just viewing the cool images! That will teach me! I was confused that some were fine and others (the later ones) looked weird!
fritzo 2y ago
A great source for stereo pairs is NOAA's aerial imagery data, consisting of various snapshots along an airplane's trajectory. For example here is a stereo pair of Desecheo Island: https://cdn.coastalscience.noaa.gov/datasets/aerialphotodb/usvi/images/797.jpg https://cdn.coastalscience.noaa.gov/datasets/aerialphotodb/u... https://cdn.coastalscience.noaa.gov/datasets/aerialphotodb/usvi/images/796.jpg https://cdn.coastalscience.noaa.gov/datasets/aerialphotodb/u... EDIT it can be tedious to discover such pairs. If only there were a tool...
LVB 2y ago
I’ve been able to view these type of pictures forever. But I’ll credit the article with today being the first time I’ve actually taken them myself, put them side by side in my notes app, and been pretty impressed with how simple it was to get a neat effect.
- moultano 2y ago
  Great! I wrote this in the hopes that more people would start making them, because I love them.
smusamashah 2y ago
Those who fail to cross eye/parallel eye these images can try looking at these through a (DIY) binocular (empty pipes/used kitchen roll should work the same). It will only work with parallel eye images though (at the end of this article).
CGamesPlay 2y ago
Since the advent of models like Depth Anything, you can now convert 2D images into this effect using them plus a bit of creative processing. Here's a non-technical overview that plugs some software and talks about the underlying models: https://www.owl3d.com/blog/2d-to-stereoscopic-3d-with-ai-depth-map-from-a-single-image https://www.owl3d.com/blog/2d-to-stereoscopic-3d-with-ai-dep... Bonus, I also found this real-time 3D-ifier for your screen: https://github.com/zjkhurry/stereopsis-anything https://github.com/zjkhurry/stereopsis-anything
whycome 2y ago
I’m surprised that phone manufacturers don’t stick cameras on opposite ends of the phone to allow the quick capture of these.
- groggo 2y ago
  They do? Well not exactly, but even with the multiple iphone cameras, you can do "spatial capture" (https://support.apple.com/guide/apple-vision-pro/capture-dev7068c3c93/visionos https://support.apple.com/guide/apple-vision-pro/capture-dev...), and see it on a Vision Pro. I don't know exactly how it works, presumably somewhat with classic stereo photography from the slightly displaced cameras (wide and ultrawide), and some more complicated computer vision tricks. But yeah just having the cameras on either side would be great, although you couldn't play around with the distance as easily.
  - whycome 2y ago
    Hm I wonder if instead of the displacement, it’s using the difference in the standard and ultrawide field of view and doing some sort of interpolation of them? Maybe even pulling data from the lidar? The fake depth of field blur/bokeh uses some of this I guess.
JKCalhoun 2y ago
To simplify capture, I've picked up a couple of digital stereo cameras (Fujifilm FinePix REAL 3D is a good one). The image quality is so-so and they're fairly affordable still on eBay (maybe $200 or so). Last summer on a road trip to Alaska, it was almost my exclusive camera for the trip. When I got back I wrote an app to take the MPO files it contains and turn them into a printable parallel-view image. The side-by-side images are intended to be printed and used in an old-fashioned stereoscope. https://github.com/EngineersNeedArt/Stereographer https://github.com/EngineersNeedArt/Stereographer
- groggo 2y ago
  3d cameras though won't let you experiment with the distance between images. It'll give you a consistent look, similar to what our eyes see, but what's cool about using one camera and moving it is you can exaggerate the distance to show depth much farther away.
jasonjmcghee 2y ago
I had to, hopefully you don't mind moultano! Same content, but all lined up and rendered the whole article in cross-view. You can now read the article and see the pictures while in cross-view. https://jasonjmcghee.github.io/you-should-make-cross-views-3d/ https://jasonjmcghee.github.io/you-should-make-cross-views-3...
- moultano 2y ago
  Clever!
- Cogito 2y ago
  Now just need to duplicate the mouse cursor to be in 3D too! I also had to shrink the window as I couldn't manage the cross view on a widescreen :)
  - jasonjmcghee 2y ago
    Yeah I didn't know how big to make the text so I figured people could just zoom out as needed lol
- bthallplz 2y ago
  This is great! I can only imagine how strange it would look to observe someone reading an article this way, but it's a great idea!
BrandoElFollito 2y ago
What I find funny is that once you get the fix, you can move your eyes around the 3D picture without losing the fix
Agingcoder 2y ago
I’d love to look at these pictures but have never succeeded. In particular, I find crossing my eyes to be a rather painful ( as in, it physically hurts ) experience so stop immediately if I try.
- jrmg 2y ago
  I can just about do it, but it messes up my ability to focus normally for ages afterwards. Doesn’t feel like it’s good for my eyes…
- veilrap 2y ago
  This is why I never do the cross-eyed version of focusing on these. For me that's always been uncofortable. Using the parallel view, or focusing out beyond the picture to make the images converge has always been easier and more comfortable for me.
jjtheblunt 2y ago
january 1983 issue of Creative Computing had an article on stereo vision, and I build the stereoscope in it, and wrote basic for my IBM PC to do this. Awesome! https://www.atarimagazines.com/creative/v9n1/162_Stereo_graphics_making_i.php https://www.atarimagazines.com/creative/v9n1/162_Stereo_grap...
perching_aix 2y ago
Often underappreciated detail when it comes to stereoscopic 3D is that the image produced is not actually fully 3D still. Even with just a single eye, it is possible to see depth: this would be via monocular depth cues, such as depth of field. If you ever wondered why 3D visuals, no matter how technically advanced, never quite felt right, this is likely the culprit. When your eyes adapt to the stereo 3D cues, the monocular cues are lost and vice versa. There are some VR technologies that do hope to achieve both at the same time using eye (and iris?) tracking, but I haven't been following the topic for a while. It's essentially a quest for a lightfield display.
- mxfh 2y ago
  The monocular depth cues are not lost; rather, the main issue with VR and stereoscopic images is the forced depth focus. This creates a mismatch between vergence and accommodation, which can interfere with natural depth perception. There is extensive research on this topic, particularly regarding the vergence-accommodation conflict: https://en.wikipedia.org/wiki/Vergence-accommodation_conflict https://en.wikipedia.org/wiki/Vergence-accommodation_conflic...
  - perching_aix 2y ago
    Yes, that's the effect I'm referring to. Maybe my wording was too sloppy.
Cogito 2y ago
My favourite related trick is to use cross viewing to solve find-the-difference puzzles. Set up so the two images (with slight differences) are next to each other, cross your eyes, and look for 'shimmering' spots - these are the differences between the images. It makes differences very easy to spot, which is pretty cool!
dividuum 2y ago
Once you learn how to cross view, you can cheat at those „find the difference“ quizzes: Cross view them and the differences will flicker.
offsky 2y ago
Is there a way to turn Apple special photos into cross view images?
groggo 2y ago
I love that this comes up every so often on hacker news. I used love Magic Eye as a kid, and have been taking stereo photos on and off ever since. Experimenting with how to take them (moving camera, from a plane, etc), and how to view them (cross view, and putting them into Meta Quest). Thanks for sharing!
ziofill 2y ago
If you are able to cross two images for the 3D effect you can also do it to spot differences like a savant in “spot the differences” games. Give it a try: https://spotthedifference.games/ https://spotthedifference.games/ You’re welcome.
- keyle 2y ago
  My mind is blown right now. This is so cool.
- __rito__ 2y ago
  Very relevant: https://news.ycombinator.com/item?id=42655870 https://news.ycombinator.com/item?id=42655870
- jy14898 2y ago
  It's interesting how the difference appears, a strange artifact. Very fun to feel like a pro clicking through the differences quickly
globular-toast 2y ago
I found these all very easy to see on my phone screen. By the end of the article I was already able to instantly "go 3d" without thinking "go cross eyed" or use tricks like looking at my nose. The problem I think most people will have is screen size. If the screen is too big then going cross eyed will be harder and might cause strain. Straight eyed can be easier, but I still think there's a limit on screen size. Magic eyes when printed are about the right size for people's heads so just work. The second problem is the pictures look half as big as soon as you "go 3d". So although it's very cool and I buy the author's point that some pictures need the depth to make sense, there's always something lost from the full size picture. On my phone it made it like looking at a postage stamp! Still I might try it myself given how easy it sounds. I imagine even a slight bit of wind would make some subjects impossible, though!
teknopaul 2y ago
Don't do this too much. Your eyes have to focus. For things close enough they can tell from the required small angle of cross-eyed movement, how to focus. These pictures (and stereograms) disconnect the focus and angle of your eyes. Do it enough and you loose the ability to focus quickly. I found it out playing with steregrams on a 286 pc a long long time ago. YMMV but I lost the ability to quickly re-focus object that you dont already know the size of; and it's a bitch.

Cross Views

173 points by moultano 2y ago

StevenNunez 2y ago

Jokes on you! I can only see from one eye at a time!

fffrantz 2y ago
Yep, same here. Discovered I was stereoblind quite late as well as I thought it was the norm and my brain just got used to it.

tombert 2y ago

I love this effect. I had a book of Magic Eye pictures as a kid, which was a similar effect. I'm not sure how practical the "crossing your eyes to get 3D" thing actually is, it makes my eyes water after a minute or so, but it's still sort of cool to see my cheapy monitor doing 3D without any special glasses.

tomw1808 2y ago
I had the same book - the one with the black border? :) There was a dolphin or something, right? So long ago, can barely remember... The water eye thing only happens to me if I cross my eyes and focus before the picture and not behind the picture. The latter takes some time to let the eyes relax, but its much more natural.
RIMR 2y ago
If you stitch the photos together seamlessly, you can display them on a VR headset in a really natural way. I take stereo images in landscape mode, stitch them together top/bottom, and then enjoy them on my Quest 2 using the Pigasus media player. If you use a 180° fisheye lens, you can immerse yourself in the scene. just make sure to keep the camera perfectly level, or you'll end up making yourself sick if you try to view the images unadjusted.
voytec 2y ago
"Wow, a sailboat!"
regularfry 2y ago
I seem to recall that Magic Eye pictures had you decross your eyes, so you were looking past the page. It was a bit harder to do.
alnwlsn 2y ago
I only learned somewhat recently that a lot of (or all?) Magic Eyes are meant to be parallel viewed instead of cross eyed. The difference was pretty impressive the first time I saw one correctly.
vrighter 2y ago
eh, you get used to it. I've watched whole movies like this

nashashmi 2y ago

I want to know why cannot the multiple cameras on my phone be used to create 3D images.

tomw1808 2y ago
They can, or? Apple calls that spatial videos, or does that work differently?
- Philpax 2y ago
  Yes, the spatial videos that iPhones can record are just stereoscopic video. This hasn't been cloned by other manufacturers because there have been very few viewing devices that they own, but that might change with Android XR.
dist-epoch 2y ago
Because they are not the same focal length? Although I'm sure software can mitigate that to some extent.
regularfry 2y ago
They're not far enough apart. Stereo vision on humans is best inside 3-5 metres, usually, and by 10 metres out is not that great. That's with pupils 65mm apart, give or take. Now scale that down to the horizontal distance between lenses on a phone. Coincidentally on mine they are about 13mm apart. You just multiply everything down linearly: my camera has the same experience at 60mm distance from an object as I do at 3m. It would be pretty useless past 2m, but also with those constraints you'd notice the quality drop off with range within a single object that was approaching 50cm depth. Now that's OK itself, you could get some useful work done with that, but there are so many provisos to it that it would be very hard to sell as a feature. To top that off it's algorithmically painful. There's a reason the commercial 3D scanners don't (typically, only) use stereo pairs; there's almost always a better way to do it.
- regularfry 2y ago
  (oh, and to get out ahead of questions: Spatial Video capture on the iphone 15 apparently uses the LIDAR sensor for the depth map, not just the cameras)

deadbabe 2y ago

I thought this would be about wigglegrams

Kerbonut 2y ago

Is it just me or do they have some of the left/right images swapped?

throw310822 2y ago
Came to say the same. Depth is inverted for me. Is it because instead of looking at each picture with the eyes straight, we cross them (and each sees the opposite picture)?
- moultano 2y ago
  If they look inverted you are probably diverging your eyes instead of crossing them. In that case the images in this section should look correct. https://moultano.wordpress.com/2025/02/24/you-should-make-cross-views/#:~:text=If%20you%20are%20able%20to%20diverge%20your%20eyes%20instead%20of%20crossing%20them%2C%20then%20arranging%20the%20images%20the%20opposite%20way%20can%20give%20you%20a%20more%20relaxing%20and%20more%20natural%20stereo%20effect.%20This%20corresponds%20to%20focusing%20past%20the%20image%20instead%20of%20in%20front%20of%20it. https://moultano.wordpress.com/2025/02/24/you-should-make-cr...
  - foobarian 2y ago
    Heh I thought you must've tested these on a teeny tiny monitor to make them work. No wonder! But of course when crossing eyes there is essentially no limit. Thanks for the clarification.
moultano 2y ago
I just went back and doubled checked, and they're all correct. If they look inverted, you are probably diverging your eyes ("parallel view") instead of crossing them. If that's more comfortable for you there is a section of images arranged with that orientation at the end of the article.
dragonwriter 2y ago
The first set are (as the text says) designed for cross-eyed viewing, the others for parallel. These use opposite left/right arrangement. So if it feels like half of them are backwards, you are maybe using the same viewing method for both sets?

zehaeva 2y ago

Ugh, there's some people out there who cannot see these. Not for a lack of trying, I've personally been trying since the 90s.

wkat4242 2y ago
It took me a while too. Especially those double images that look totally contorted and only come out when you relax your focus. It took ages but suddenly they popped and now i can do them every time. Once they came through they were crystal clear.
kookster310 2y ago
The trick for me was to completely cross my eyes and produce the double images, then slowly uncross/cross them until I could start to see the image, which eventually clears up.
stewarts 2y ago
I am with you. I could also never see the hidden image things. Been trying for 40 years.
dist-epoch 2y ago
Do you manage to align the two small white squares above each picture so they are on top of each other?
- moultano 2y ago
  Yes.
tantalor 2y ago
There are two communities, you need to find out which one you belong to. https://www.reddit.com/r/CrossView https://www.reddit.com/r/CrossView https://www.reddit.com/r/ParallelView https://www.reddit.com/r/ParallelView There is a test image you can try: https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fg5ilwgk99r781.jpg https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2Fg... Whichever "view" looks to be closer is the one you should use.

EvanAnderson 2y ago

I've done this with my SLR. Moving the camera different amounts can give a more pronounced effect, however it can be more difficult to get the image to converge. I had a lot of fun with doing this 20 years ago. Sadly, my visual acuity has become significantly different between my eyes (even w/ correction) and the enjoyment of 3D displays has really diminished as as result. Just musing because I'm working and busy: I wonder how difficult it would be to do video. (Obviously you'd have to shoot two videos in parallel versus just moving the camera and shooting again.) Converting existing 3D videos to a cross-eyed viewing format would probably be the easiest way to experiment with it. I wonder if anybody has done that. I've never looked at 3D movie formats before. I always assumed it was two interleaved streams.

wkat4242 2y ago
You should move it by the distance of your pupils for the best effect. Mine is bog standard 63mm so I'm lucky. If you get it wrong things will look too big or too small and the 3D effect will be softer or too pronounced.
- llm_trw 2y ago
  The point is that you can force the respective of a giant or an ant if you so choose. Using two cameras I had a time lapse of a fog coming in where you could see the 3d structure becuase they were at two different streets looking out. Like op this was done nearly 20 years ago. Now you don't even get fog any more.
  - Jarmsy 2y ago
    I remember reading about a physical device someone constructed with mirrors (I think at an early burning man) that gave you the experience of a huge inter ocular distance to get a giant's eye view. I've always wanted to try one (or the opposite to experience a tiny inter ocular distance).
    - Jarmsy 2y ago

Karawebnetwork 2y ago

When they wrote "your screen can display 3D photos", I thought it would be a hardware hack and not something that depends on a human physiology hack. Something like stereoscopic GIFs come to mind, e.g. https://tenor.com/fr-CA/view/dain-stereoscopic-daingifs-3d-monster-gif-9119977 https://tenor.com/fr-CA/view/dain-stereoscopic-daingifs-3d-m... In other words, taking the two images and swapping them quickly creates the illusion of depth. Edit: Looking into it, there's a word for it. Wiggle stereoscopy: https://en.wikipedia.org/wiki/Wiggle_stereoscopy https://en.wikipedia.org/wiki/Wiggle_stereoscopy

zro 2y ago
There's a whole bunch of these over at https://old.reddit.com/r/wigglegrams/ https://old.reddit.com/r/wigglegrams/ if you want more

stronglikedan 2y ago

> Your screen can display 3D photos. That's a stretch, but I guess clickbait is required to get engagement nowadays.

moultano 2y ago
As long as you don't regret the click, I don't regret baiting the click. :)
ellenhp 2y ago
> nowadays People have been writing provocative titles for things since before the internet.

thih9 2y ago

I prefer wigglegrams. If you're looking for an example - Wikipedia page has one from 1927[1]! [1]: https://en.wikipedia.org/wiki/Wiggle_stereoscopy https://en.wikipedia.org/wiki/Wiggle_stereoscopy

blululu 2y ago
Was going to say the same thing. Presenting stereo pairs has a lot of layout and resolution issues to say nothing of the fact that some people have stereo blindness to varying degrees (lazy eye is an extreme case). The author is correct that stereo depth can greatly enhance an image, but a wigglegram does this at full resolution with no visual puzzle solving.
ilyagr 2y ago
Thank you! I have not, to this day, have been able to see any Magic Eye/Cross Eyed or similar images. A wigglegram is immediately trivial. I'd probably most appreciate a layout with one frame on the left, the wigglegram in the middle, and the other frame on the right, so that I can get a sense of both the distances and the detail.
James_K 2y ago
I'm slightly suspicious that this comment was written by a bird.
dagss 2y ago
WHAT... this is the first time in my life I have been able to see 3D with one eye! Closing one eye and I still see the depth effect. Main brain works very differently than I assumed... With this effect I guess one could make even people who are blind on one eye see in 3D

haunter 2y ago

Nintendo 3DS gang rise up! Though it wasn't perfect or useful that much it was still a nice feature, made some fun photos with it.

ben7799 2y ago

I can generally see the Magic Eye pictures very well.. these are way harder. The tiny thumbnails at the bottom of the page work, but the larger images I can't cross my eyes enough. I think it depends greatly on getting the screen/image size just the right size and also getting the viewing distance right. On large monitors it seems harder to see.

on_the_train 2y ago
I believe the author switched left and right. Because the inverse ones at the bottom work fine
- moultano 2y ago
  Magic eye pictures are viewed by diverging your eyes, so the "parallel view" versions at the bottom work correctly with that method. "Cross view" pictures require converging your eyes, so the images have to be in the opposite position from what your eye would see.
  - ben7799 2y ago
    You're right.. guess I always thought Magic Eye was converged. Once I look at the ones at the bottom and just zoom in/out in the browser I can see them perfectly. I have a 33" monitor and seeing them means sitting much closer than normal and then zooming out in the browser.
  - deleted 2y ago
    [deleted]
  - on_the_train 2y ago
    Nah, magic eye is crossing, at least the ones I know. And I can only do crossing
moultano 2y ago
Yes, making them smaller certainly helps.
2y ago

colingauvin 2y ago

This is very common in structural biology papers, where you need to make figure of complex 3D arrangements of atoms, but the figures must be printed in 2D. Typically using molecular modeling software, you find your view of choice. Then you rotate +- 0.5° and render two images, and put those side by side as a stereo pair figure. It takes quite a bit of practice to see them well: https://spdbv.unil.ch/TheMolecularLevel/0Help/StereoView.html https://spdbv.unil.ch/TheMolecularLevel/0Help/StereoView.htm...

regularfry 2y ago
I did this on a school project back in the 90's, with a structure of quinol clathrate that was completely wrong but very pretty. I was very into povray at the time. My chemistry teacher didn't quite know what to make of it...
BrandoElFollito 2y ago
Thanks for that! It is quite impressive and I learned to see the 3D molecule on first try. I remember seeing something similar, but made of an array of dots (you did not know what was behind the doors until you see it by crossing your eyes)
groggo 2y ago
technically rotation is going to end up giving a slightly different result than lateral displacement, right? but it's very similar for small distances.

dandsupernig 2y ago

[flagged]

throwaway494932 2y ago

The video game Magic Carpet had a couple of 3D modes, anaglyph 3d requiring blue/red classes, and stereogram mode [1]. The latter was not really usable, but it was a cool trick, expecially for the time ('94). [1] https://youtu.be/iZT-S2F191I?si=8k9jniqA98wgq0Hu&t=1090 https://youtu.be/iZT-S2F191I?si=8k9jniqA98wgq0Hu&t=1090

vrighter 2y ago
i once found a renderer for quake 2 that rendered in stereograms. Managed to make it through the first level

lopatamd 2y ago

[dead]

rahimnathwani 2y ago

most stereograms are designed to look correct when you cross your eyes This is how I look at stereograms (looking nearer than the page), but at least some of the images on this page seem like they're designed for the other way around (looking in the distance, beyond the page). This one looks weird when I look at it cross eyed, but fine when I look at the other way. https://moultano.wordpress.com/wp-content/uploads/2025/02/17405320419888595852203168102922.jpg https://moultano.wordpress.com/wp-content/uploads/2025/02/17...

moultano 2y ago
Yes, the ones at the bottom, in the "Parallel View" section are designed to be viewed the other way.
- rahimnathwani 2y ago
  Sorry, I stopped reading part way and was just viewing the cool images! That will teach me! I was confused that some were fine and others (the later ones) looked weird!

fritzo 2y ago

A great source for stereo pairs is NOAA's aerial imagery data, consisting of various snapshots along an airplane's trajectory. For example here is a stereo pair of Desecheo Island: https://cdn.coastalscience.noaa.gov/datasets/aerialphotodb/usvi/images/797.jpg https://cdn.coastalscience.noaa.gov/datasets/aerialphotodb/u... https://cdn.coastalscience.noaa.gov/datasets/aerialphotodb/usvi/images/796.jpg https://cdn.coastalscience.noaa.gov/datasets/aerialphotodb/u... EDIT it can be tedious to discover such pairs. If only there were a tool...

LVB 2y ago

I’ve been able to view these type of pictures forever. But I’ll credit the article with today being the first time I’ve actually taken them myself, put them side by side in my notes app, and been pretty impressed with how simple it was to get a neat effect.

moultano 2y ago
Great! I wrote this in the hopes that more people would start making them, because I love them.

smusamashah 2y ago

Those who fail to cross eye/parallel eye these images can try looking at these through a (DIY) binocular (empty pipes/used kitchen roll should work the same). It will only work with parallel eye images though (at the end of this article).

CGamesPlay 2y ago

Since the advent of models like Depth Anything, you can now convert 2D images into this effect using them plus a bit of creative processing. Here's a non-technical overview that plugs some software and talks about the underlying models: https://www.owl3d.com/blog/2d-to-stereoscopic-3d-with-ai-depth-map-from-a-single-image https://www.owl3d.com/blog/2d-to-stereoscopic-3d-with-ai-dep... Bonus, I also found this real-time 3D-ifier for your screen: https://github.com/zjkhurry/stereopsis-anything https://github.com/zjkhurry/stereopsis-anything

whycome 2y ago

I’m surprised that phone manufacturers don’t stick cameras on opposite ends of the phone to allow the quick capture of these.

groggo 2y ago
They do? Well not exactly, but even with the multiple iphone cameras, you can do "spatial capture" (https://support.apple.com/guide/apple-vision-pro/capture-dev7068c3c93/visionos https://support.apple.com/guide/apple-vision-pro/capture-dev...), and see it on a Vision Pro. I don't know exactly how it works, presumably somewhat with classic stereo photography from the slightly displaced cameras (wide and ultrawide), and some more complicated computer vision tricks. But yeah just having the cameras on either side would be great, although you couldn't play around with the distance as easily.
- whycome 2y ago
  Hm I wonder if instead of the displacement, it’s using the difference in the standard and ultrawide field of view and doing some sort of interpolation of them? Maybe even pulling data from the lidar? The fake depth of field blur/bokeh uses some of this I guess.

JKCalhoun 2y ago

To simplify capture, I've picked up a couple of digital stereo cameras (Fujifilm FinePix REAL 3D is a good one). The image quality is so-so and they're fairly affordable still on eBay (maybe $200 or so). Last summer on a road trip to Alaska, it was almost my exclusive camera for the trip. When I got back I wrote an app to take the MPO files it contains and turn them into a printable parallel-view image. The side-by-side images are intended to be printed and used in an old-fashioned stereoscope. https://github.com/EngineersNeedArt/Stereographer https://github.com/EngineersNeedArt/Stereographer

groggo 2y ago
3d cameras though won't let you experiment with the distance between images. It'll give you a consistent look, similar to what our eyes see, but what's cool about using one camera and moving it is you can exaggerate the distance to show depth much farther away.

jasonjmcghee 2y ago

I had to, hopefully you don't mind moultano! Same content, but all lined up and rendered the whole article in cross-view. You can now read the article and see the pictures while in cross-view. https://jasonjmcghee.github.io/you-should-make-cross-views-3d/ https://jasonjmcghee.github.io/you-should-make-cross-views-3...

moultano 2y ago
Clever!
Cogito 2y ago
Now just need to duplicate the mouse cursor to be in 3D too! I also had to shrink the window as I couldn't manage the cross view on a widescreen :)
- jasonjmcghee 2y ago
  Yeah I didn't know how big to make the text so I figured people could just zoom out as needed lol
bthallplz 2y ago
This is great! I can only imagine how strange it would look to observe someone reading an article this way, but it's a great idea!

BrandoElFollito 2y ago

What I find funny is that once you get the fix, you can move your eyes around the 3D picture without losing the fix

Agingcoder 2y ago

I’d love to look at these pictures but have never succeeded. In particular, I find crossing my eyes to be a rather painful ( as in, it physically hurts ) experience so stop immediately if I try.

jrmg 2y ago
I can just about do it, but it messes up my ability to focus normally for ages afterwards. Doesn’t feel like it’s good for my eyes…
veilrap 2y ago
This is why I never do the cross-eyed version of focusing on these. For me that's always been uncofortable. Using the parallel view, or focusing out beyond the picture to make the images converge has always been easier and more comfortable for me.

jjtheblunt 2y ago

january 1983 issue of Creative Computing had an article on stereo vision, and I build the stereoscope in it, and wrote basic for my IBM PC to do this. Awesome! https://www.atarimagazines.com/creative/v9n1/162_Stereo_graphics_making_i.php https://www.atarimagazines.com/creative/v9n1/162_Stereo_grap...

perching_aix 2y ago

Often underappreciated detail when it comes to stereoscopic 3D is that the image produced is not actually fully 3D still. Even with just a single eye, it is possible to see depth: this would be via monocular depth cues, such as depth of field. If you ever wondered why 3D visuals, no matter how technically advanced, never quite felt right, this is likely the culprit. When your eyes adapt to the stereo 3D cues, the monocular cues are lost and vice versa. There are some VR technologies that do hope to achieve both at the same time using eye (and iris?) tracking, but I haven't been following the topic for a while. It's essentially a quest for a lightfield display.

mxfh 2y ago
The monocular depth cues are not lost; rather, the main issue with VR and stereoscopic images is the forced depth focus. This creates a mismatch between vergence and accommodation, which can interfere with natural depth perception. There is extensive research on this topic, particularly regarding the vergence-accommodation conflict: https://en.wikipedia.org/wiki/Vergence-accommodation_conflict https://en.wikipedia.org/wiki/Vergence-accommodation_conflic...
- perching_aix 2y ago
  Yes, that's the effect I'm referring to. Maybe my wording was too sloppy.

Cogito 2y ago

My favourite related trick is to use cross viewing to solve find-the-difference puzzles. Set up so the two images (with slight differences) are next to each other, cross your eyes, and look for 'shimmering' spots - these are the differences between the images. It makes differences very easy to spot, which is pretty cool!

dividuum 2y ago

Once you learn how to cross view, you can cheat at those „find the difference“ quizzes: Cross view them and the differences will flicker.

offsky 2y ago

Is there a way to turn Apple special photos into cross view images?

groggo 2y ago

I love that this comes up every so often on hacker news. I used love Magic Eye as a kid, and have been taking stereo photos on and off ever since. Experimenting with how to take them (moving camera, from a plane, etc), and how to view them (cross view, and putting them into Meta Quest). Thanks for sharing!

ziofill 2y ago

If you are able to cross two images for the 3D effect you can also do it to spot differences like a savant in “spot the differences” games. Give it a try: https://spotthedifference.games/ https://spotthedifference.games/ You’re welcome.

keyle 2y ago
My mind is blown right now. This is so cool.
__rito__ 2y ago
Very relevant: https://news.ycombinator.com/item?id=42655870 https://news.ycombinator.com/item?id=42655870
jy14898 2y ago
It's interesting how the difference appears, a strange artifact. Very fun to feel like a pro clicking through the differences quickly

globular-toast 2y ago

I found these all very easy to see on my phone screen. By the end of the article I was already able to instantly "go 3d" without thinking "go cross eyed" or use tricks like looking at my nose. The problem I think most people will have is screen size. If the screen is too big then going cross eyed will be harder and might cause strain. Straight eyed can be easier, but I still think there's a limit on screen size. Magic eyes when printed are about the right size for people's heads so just work. The second problem is the pictures look half as big as soon as you "go 3d". So although it's very cool and I buy the author's point that some pictures need the depth to make sense, there's always something lost from the full size picture. On my phone it made it like looking at a postage stamp! Still I might try it myself given how easy it sounds. I imagine even a slight bit of wind would make some subjects impossible, though!

teknopaul 2y ago

Don't do this too much. Your eyes have to focus. For things close enough they can tell from the required small angle of cross-eyed movement, how to focus. These pictures (and stereograms) disconnect the focus and angle of your eyes. Do it enough and you loose the ability to focus quickly. I found it out playing with steregrams on a 286 pc a long long time ago. YMMV but I lost the ability to quickly re-focus object that you dont already know the size of; and it's a bitch.