Questions about Stereoscopic 3-D

  • Thread starter tade
  • Start date
In summary, a technician would need to cut around objects in a photo and slide them to the right or left to create a 3D effect. Without the assistance of a computer, the task of creating a realistically good 3D effect will be painstaking.
  • #1
tade
702
24
When we watch 3-D films in the cinema, some objects appear to protrude, others recess. How would a technician control which objects protrude and which recess?

Also, why do the 3-D images sometimes appear like cardboard cutouts?
 
Engineering news on Phys.org
  • #2
tade said:
When we watch 3-D films in the cinema, some objects appear to protrude, others recess. How would a technician control which objects protrude and which recess?
I guess you are talking about computer generated images, rather than those taken by a pair of cameras?

Take a photo of any scene and make a second copy of that photo. Carefully cut around a few objects in that second photo and slide some of them slightly to the right, and others to the left, relative to the rest of what's in the photo. Now, superimpose that pair of photos using your stereoscopic vision. The objects whose image you moved to one side appear recessed in 3D, the objects you moved in the other direction will appear to have come forward off the photo's background.

Also, why do the 3-D images sometimes appear like cardboard cutouts?
If you want a model's nose to appear closer to the viewer than that model's face, then you must slide the nose a tiny bit further to the side than you slide the face itself. :approve:

You can see that without the assistance of a computer the task of creating a realistically good 3-D effect will be painstaking.
 
  • #3
NascentOxygen said:
I guess you are talking about computer generated images, rather than those taken by a pair of cameras?

Take a photo of any scene and make a second copy of that photo. Carefully cut around a few objects in that second photo and slide some of them slightly to the right, and others to the left, relative to the rest of what's in the photo. Now, superimpose that pair of photos using your stereoscopic vision. The objects whose image you moved to one side appear recessed in 3D, the objects you moved in the other direction will appear to have come forward off the photo's background.


If you want a model's nose to appear closer to the viewer than that model's face, then you must slide the nose a tiny bit further to the side than you slide the face itself. :approve:

You can see that without the assistance of a computer the task of creating a realistically good 3-D effect will be painstaking.

So, if I was converting a 2D video into 3D, I might have to do it "manually", and this will result in the cardboard-cutout effect?
 
  • #4
Whether "manually" or by using the computerised equivalent basic technique, that outcome will be as I described. So a crude conversion of a football give it the appearance of a flat lollypop. You'd need to shift different parts of its surface by different amounts to give it a surface with realistic 3D depth.

attachment.php?attachmentid=57358.png
 

Attachments

  • dots.png
    dots.png
    791 bytes · Views: 540
Last edited:
  • #5
NascentOxygen said:
Whether "manually" or by using the computerised equivalent basic technique, that outcome will be as I described. So a crude conversion of a football give it the appearance of a flat lollypop. You'd need to shift different parts of its surface by different amounts to give it a surface with realistic 3D depth.

attachment.php?attachmentid=57358.png

Will this problem exist with the footage from 3D Cameras? i.e. Cameras with two lenses
 
  • #6
tade said:
Will this problem exist with the footage from 3D Cameras? i.e. Cameras with two lenses
I don't expect it would ― the cameras record precisely what the eyes would see. However, while I've dabbled in computer-generated 3D, I know nothing about proper 3D photography.

Did you see the 3D effect in the pic I attached?
 
  • #7
NascentOxygen said:
I don't expect it would ― the cameras record precisely what the eyes would see. However, while I've dabbled in computer-generated 3D, I know nothing about proper 3D photography.

Did you see the 3D effect in the pic I attached?

Samsung released a phone with 3D Camera and a lenticular 3D display.


I don't know how to make it work. :blushing:
 
  • #8
tade said:
I don't know how to make it work. :blushing:
You have been short-changed if your science education overlooked an introduction to viewing random dot stereograms. :wink:

Practise on these. http://www.eyecanlearn.com/random_dot_stereogram.htm [Broken]

Disclaimer: persons without sight in both eyes will be unable to view the 3D effect
 
Last edited by a moderator:
  • #9
NascentOxygen said:
You have been short-changed if your science education overlooked an introduction to viewing random dot stereograms. :wink:

Practise on these. http://www.eyecanlearn.com/random_dot_stereogram.htm [Broken]

Disclaimer: persons without sight in both eyes will be unable to view the 3D effect

No ****, schools wouldn't give a damn about this.

Those are awesome, it's as though I'm looking at a wall that's behind my monitor.
 
Last edited by a moderator:
  • #10
Now go back to the simple pic I generated. It works the same way, and you can easily see how I modified the first image.
 
  • #11
NascentOxygen said:
Now go back to the simple pic I generated. It works the same way, and you can easily see how I modified the first image.

Ok, I managed to see some floaty letters

Yeah, you shifted the d and the g.
 
  • #12
g is part of the background. I shifted d and f.
 
  • #13
NascentOxygen said:
g is part of the background. I shifted d and f.

oops. funny thing is, I believe I still have depth perception when I cover one eye and look around my room.
 
  • #14
tade said:
oops. funny thing is, I believe I still have depth perception when I cover one eye and look around my room.

though I shouldn't have depth perception, right?
 
  • #15
Using only one eye you lack depth perception. But I think we acquire much depth information by a number of alternative techniques. You know that a drink can is smaller than a chair, so if the drink can looms larger then we infer that it is closer. (But you could be tricked by someone fabricating a gigantic can and placing it more distant than the chair.) Also, by moving your head to one side you can see which objects appear to undergo the greater shift relative to the background, indicating they are closer. In addition, you can discern objects which are close by the effort the eye muscle must exert to focus the object's image.
 
  • #16
NascentOxygen said:
Using only one eye you lack depth perception. But I think we acquire much depth information by a number of alternative techniques. You know that a drink can is smaller than a chair, so if the drink can looms larger then we infer that it is closer. (But you could be tricked by someone fabricating a gigantic can and placing it more distant than the chair.) Also, by moving your head to one side you can see which objects appear to undergo the greater shift relative to the background, indicating they are closer. In addition, you can discern objects which are close by the effort the eye muscle must exert to focus the object's image.

But my depth perception doesn't disappear when I cover one eye. At least, I have this strong belief that it doesn't. It's probably psychological.
 
  • #17
With only one eye, you have no stereoscopic vision, so lack the depth perception due to stereo vision. But you still have other means for perceiving depth, the ones I outlined.
 
  • #18
I see.

So that's why I don't notice any immediate loss in my depth capability
 

1. What is stereoscopic 3-D?

Stereoscopic 3-D is a technology that creates the illusion of depth in a two-dimensional image. It uses two slightly different images, one for the left eye and one for the right eye, to create the perception of depth.

2. How does stereoscopic 3-D work?

To create the illusion of depth, stereoscopic 3-D uses two methods: passive and active. Passive 3-D uses glasses with different colored lenses to filter the images for each eye, while active 3-D uses glasses with LCD shutters that open and close rapidly to show the correct image for each eye.

3. What are the benefits of using stereoscopic 3-D?

Stereoscopic 3-D can enhance the viewing experience by making images and movies appear more lifelike and immersive. It can also provide a better understanding of complex data and enhance educational materials.

4. Are there any potential negative effects of stereoscopic 3-D?

Some people may experience discomfort or headaches when viewing stereoscopic 3-D content. There have also been concerns about the long-term effects on eye health, but more research is needed to fully understand these potential risks.

5. How is stereoscopic 3-D used in different industries?

Stereoscopic 3-D technology is used in a variety of industries, including entertainment, education, medicine, and engineering. It is commonly used in movies, video games, and virtual reality experiences, but it also has practical applications in fields such as architecture, product design, and medical imaging.

Similar threads

Replies
7
Views
1K
  • Sci-Fi Writing and World Building
Replies
3
Views
631
Replies
1
Views
1K
Replies
3
Views
998
  • Other Physics Topics
Replies
2
Views
1K
  • Science Fiction and Fantasy Media
Replies
2
Views
2K
  • General Engineering
Replies
25
Views
2K
  • Differential Geometry
Replies
4
Views
2K
  • Programming and Computer Science
Replies
1
Views
719
  • Precalculus Mathematics Homework Help
Replies
7
Views
772
Back
Top