Mirror, 2D or 3D?

[xprynx]

We say that a film or a photo is 2D because the surface of a picture or a movie screen is 2D,eventhough the photo or movie gives a 3D appearance.

Now consider a mirror image.Mirror surface is 2D but shows a real 3D image. What should be the dimensional specification of a mirror image? is it 2D or 3D?

[InfiniteNow]

It's 2D. We just interpret the incoming sensory data into 3D from our experience. Extrapolate...

[Boerseun]

I guess the mirror surface would be 2D, but the image seen would be 3D.

And the image would only be 3D, 'cause we've got two eyes. Poke one eye out, and everything would be 2D.

 

People make too much of 3D - the world's best camera can only see in 2D, cause it's got only one perspective. 3D is a concatenation of two individual 2D pictures in order to see a single 3D picture.

[Guest chendoh]

Take two mirrors, have one perpendicular to the other to form a right angle.

Position yourself so you can see your image ( at least top of head to top of shoulders. ) in the corner.

 

Align them to produce one image, its still 2D, but you have an image of how people

perceive you. Similier to a photograph

 

If you look at it long enough you'll swear your image comes away from the mirrors. :hyper:

 

The amazing world of refraction............chendoh

[Tormod]

What should be the dimensional specification of a mirror image?

 

A mirror image is depending on what it mirrors. A flat mirror in 3D space will have a 2D surface. A curved mirror in 3D space will have a 3D surface. The image it shows will still be 2D.

 

The mirror is just reflecting electromagnetic waves. The time it takes for a light beam to reach you depends on how far away it is in the first place - therefore the mirror correctly gives an impression of 3D even if it is just a 2D image.

[Qfwfq]

A mirror image is definitely 3D and this can be established even with only one eye Boerseun.

 

There was a thread that discussed this matter, I found it by searching this forum for titles with the words 'mirror' and 'image'.

 

http://hypography.com/forums/physics-mathematics/3758-seekers-questions-mirror-virtual-image.html?highlight=mirror+image

[Tormod]

Q, I don't see how that thread supports the 3D mirror image idea...what am I missing?

[Qfwfq]

I don't know if the whole entire thread supports it :hihi: but I talked about parallax there and how it isn't like a photograph at all. Anyway I just thought this thread is a bit of a dupe.

[Boerseun]

I think we're getting confused between objects and images. A mirror's surface would be 2D, seeing as it's a flat plane. Twisted into a funhouse mirror, like Tormod said, would of course make it 3D. The image, however, would be 3D.

 

Interesting thing I read about a couple of years ago, dunno if it's true, though:

 

Any n-dimensional image can be represented on an (n-1)-dimensional medium.

For instance, a 2D medium (paper) can be used to show a 3D object (an isometric drawing). And a 3D medium (television) can be used to show 4D stuff. (A TV is 3D, not with the normal x,y and z axis giving it spatial depth, but x,y and time - seeing as there's motion. The z-axis is the illusory one, alluding to a higher dimension...)

 

And then, if this is true, if we had a true 4D medium, we should be able to picture a 5th dimension. A 4D medium, having x,y,z and time, would, probably, be a holograph. What the 5th dimension would look like, is anybody's guess, but should be viewable with a holographical projector.

And not viewable as the actual thing, but represented as an isometric drawing would illustrate the third dimension. And once we figure that out, and can figure out, somehow, how to build a 5D medium, heck - we can view representations of the 6th dimension! And so on...

 

I don't know wether the above is true, though - I don't know how you're going to represent a 2D image in a 1D medium...

 

Interesting...:shrug:

[cwes99_03]

Entirely true. In fact it goes deeper than that. I created a 4-d and a 5-d lattice of resistors on a 2-d circuit board (the type you use in a beginners electronics lab) I'll have to dig and find the pictures. I once had them posted on my geocities site, but that has long since been torn down.

[TheFaithfulStone]

Actually, even the 4D image of television can be portrayed (although we can't tell what the heck it's supposed to be) even in 2D. Ever had the vertical scan go out on your television? Every line get's drawn in a single location on the screen - it looks like a flickering line.

 

NOW, given that you know what the refresh rate of a television is, and what the frame rate of broadcast TV is (I think 29.97 for PAL) if you could record that 2D broadcast it would be possible to later mathematically construct it back into it's 2D representation.

 

Which means, even if you could only perceive two dimensions, a spatial and a time - you could construct a picture of the world which included more "real" spatial dimensions than what you were capable of percieving, provided you had the necessary information.

 

Put that in your pipe, along with some string theory, and give it a smoke.

 

Perhaps all spatial dimenions are a matter of perception.

 

What would a fourth spatial coordinate look like?

 

TFS

[kay, now my mind is boggled]

[Qfwfq]

You can represent even more than 4 dimensions on a 2D surface but that isn't the same as a mirror image, you don't see the parallax change if you move transversally.

[TheFaithfulStone]

No, no, no. It isn't. You're absolutely correct Q.

 

I was just saying that you don't even have to see extra dimensions (or have the ability to measure them directly) in order for them to really be there.

 

But you're right, you couldn't see the parallax change, so you couldn't calculate the "third dimension" directly, you'd have to calculate the second one first, and then the third.

 

TFS

[cwes99_03]

Yes, exactly Q, you are correct.

 

My experiments were simply to find a simpler way to create multidimensional lattices of resistors without creating this humongous ball of wires and resistors which would be very hard to recognize as anything other than a big ball of wiring in 3-d.

The importance of putting something into dimensions higher than 3 is to realize that for something to be truly n-d each internal node must have 2n wires coming out of it (whereas the corners and sides have fewer).

 

It took me about 12 hours of sitting in a room to come up with a method that work work for n-dimensions on a 2-d board with sides as long as you want (considering you have enough boards to connect up.)

[xprynx]

The thing that an n dimensional medium can represent n+1 dimensional object can be debated true in case of drawings on paper etc... But see the real image formation on a mirror.We see the things around us(in 3 dimension) due to the reflection of light from those objects which is being processed by our eyes.Now see a mirror image.Here the reflection takes place two times , one is:reflection to the mirror and the second: from mirror to our eyes.What is the change that this series of reflection can make to the dimensional appearance of the object from a single reflection that we originally see???