The first practical attempt to create an invisible aircraft was in
the 1940s, with the U.S. Navy operation "Yahootie". Observers on
German U-boats cruising on the surface during daylight, visually
spotted U.S. Navy bombers before the planes could attack, allowing
the submarines to dive safely away.
A series of bright lights were arrayed on the wings and propeller
hubs of the sub-hunter planes. The bomber crews adjusted the lights
to match the natural background light behind the aircraft, masking
itself against the sky. This so-called "isoluminous" principle is
based upon the perception that different objects displaying the
same brightness seem indistinguishable from each other.
More recently with the development of flexible display panels for
computer screens, it may be possible to create a suit for a man or
an envelope for a vehicle that has active camoflage similar to
that exhibited by squid or octopi. By having cameras arranged to
panaramically view the surounding scene, the image seen behind is
displayed on the front, that seen in front is displayed behind,
and the same for left and right.
.unionised - 1-8-2006 at 09:00
Logically, if your "eyes" are invisible, you can't see. Of course, with small cameras this might not matter too much.Twospoons - 1-8-2006 at 14:33
Quote:
Originally posted by franklyn
it may be possible to create a suit for a man or
an envelope for a vehicle that has active camoflage similar to
that exhibited by squid or octopi.
.
Its been done. Saw an article in New Scientist some time back where a guy in Japan has made an "invisibility cloak" just as you describe. If you
search the New Scientist website you may be able to fine the article.IrC - 1-8-2006 at 14:47
Could you post that pdf again? The link is dead.franklyn - 4-8-2006 at 18:02
Yes I am aware of that, it is little more than an artistic novelty which only illustrates the principle.
I can charitably say , it is definitely not ready for prime time.
Quote:
Originally posted by unionised
Logically, if your "eyes" are invisible, you can't see.
I don't know, one way mirrors allow one to see without being seen.
There are many effects which can be exploited to produce an illusion
of invisibility,
If one works within the parameter of the limitations inherent to
each.
1 ) I recall having read of a polymer developed to coat camera lenses that entirely
eliminates surface reflections and dispersion. The proposal was made that an optically
polished wine goblet of high refractive glass crystal, coated with this polymer would in
subdued lighting vanish from sight. Any liquid content poured into this glass would appear
to be floating in midair. This is much the same as when gem quality diamonds placed in
a glass of water blend in so they cannot be distinguished from the water.
2 ) A similar effect using an aerogel block ( a translucent zeolite having the appearance
of solid smoke ) placed on a sidewalk in hazy daylight, effectively disappears against the
concrete background. A performer then stepping up onto it would seem to be hovering
above the ground without visible support.
3 ) Holograms are completely convincing 3 dimensional images made by laser light on
photographic film. A strip made into a squat cylinder holding the 360 degree view of an
object is essentially a continuous movie without distinct frames. This image may be
viewed from any side and appears to be an object within a display case, until one looks
inside from above and sees that it is empty.
Similarly a rotunda exhibiting the panoramic view of its surroundings where it was made
would blend seamlessly with its background. The interior unseen from the outside would
be hidden from view. The illusion would be spoiled when someone would walk behind it
and disappear from view, then re-emerge on the other opposite side.
4 ) The oldest method is that of stage magic in which a space is hidden within what
looks like an empty hollow framework, by channeling the background image around the
enclosed space with mirrors in the form of a periscope.
5 ) The most absolute invisibility is that which is cannot be perceived at all because it
lies outside the visual field. The macula is the part of the retina of the eye that is the
center of visual focus. Adjacent to this is the optic nerve which itself is blind. This
produces a gap in the visual field which is not readily perceptible but very real.
Whatever is focused into this blind spot literally cannot be seen.
For a demonstration of this see -> http://home.earthlink.net/~daliblume/KnowThis/BlindSpot.html
.
[Edited on 5-8-2006 by franklyn]franklyn - 15-9-2006 at 23:13
U P D A T E
Its a lot closer than you think
attached photocopy of October 2006 Popular Science
[Edited on 17-9-2006 by franklyn]
Nerro - 16-9-2006 at 01:54
If you can really make an object the size of a B-2 Bomber disappear you can bet your sweet little ass they're working on it frantically for years
allready Give it some time and you'll see it on discovery channel eventually
unionised - 16-9-2006 at 09:26
Are you sure that isn't the April 1st issue?
These "metamaterials" where the light travels through them faster than c seem pretty implausible to me.12AX7 - 16-9-2006 at 09:54
Sez October.
Can you please edit that picture? I can't read any replies with it bulging there.
TimNerro - 16-9-2006 at 11:47
Oh btw, a substance through which c > c(vacuum) is bs. The refractive index would be negative, how would you make something like that?12AX7 - 16-9-2006 at 12:06
wow, that's just weird... I'm going to look into that for sure!franklyn - 16-9-2006 at 19:10
Quote:
Originally posted by 12AX7Can you please edit that picture? I can't read any replies with it bulging there.
Don't you see a scroll bar below like the verticle one on the left side? You can shift the image left or right , trouble is that
it's white and hard to see.
I tried to be faithful to how it appears in print, and yes this is hot off the press for next month.
[Edited on 17-9-2006 by franklyn]12AX7 - 16-9-2006 at 19:31
Ya and I have to wag the scroll bar back and forth to read each line. Fuck that.richard - 18-10-2006 at 01:58
I would love a car like that. But it would be a bit awkard not being able to see out.
New Developments for the prospect of invisibility _
U P D A T E24-04-2007 http://www.whatsnextnetwork.com/technology/index.php/2007/04...
Quote _
A key factor in the design is the ability to reduce the "index of refraction" to less than 1. Refraction occurs as electromagnetic waves, including
light, bend when passing from one material into another. Refraction causes the bent-stick-in-water effect, which occurs when a stick placed in a glass
of water appears bent when viewed from the outside. Each material has its own refraction index, which describes how much light will bend in that
particular material and defines how much the speed of light slows down while passing through a material.
Natural materials typically have refractive indices greater than 1. The new design reduces a refractive index to values gradually varying from zero at
the inner surface of the cloak, to 1 at the outer surface of the cloak, which is required to guide light around the cloaked object.
Creating the tiny needles would require the same sort of equipment already used to fabricate nanotech devices. The needles in the theoretical design
are about as wide as 10 nanometers, or billionths of a meter, and as long as hundreds of nanometers. They would be arranged in layers emanating from a
central spoke in a cylindrical shape. A single nanometer is roughly the size of 20 hydrogen atoms strung together.
Although the design would work only for one frequency, it still might have applications, such as producing a cloaking system to make soldiers
invisible to night-vision goggles.
Image occluding technology has been utilized for some time
in the microwave spectrum for stealth aircraft application.
The latest move is to extend capability into shorter wavelength
milimeter and infrared spectrums.
I think that optical fibers could make something nearly invisible without the need for cameras and projectors...
Optical fibers can bend light arround an object and hide it like if you see throught it.
You would need to be precise regarding the disposition of the fibers...the input and output must be perfectly in line in a way the image seen in front
is what lies behind and reversely.
Also the fibers must be of high quality.Morgan - 25-11-2013 at 13:44
Maybe one day they will come up with something similar to octopus skin cells. franklyn - 17-12-2013 at 15:51
Everyone is so worried about cameras or whatever device being visible from the outside of the camouflage, but I don't see how that would matter. If I
suspended a 1/2" diameter camera lens 15 feet from you, while you were walking, would you even notice it? We have trouble finding our keys on a table
in front of us sometimes, why would a tiny visible part of the camouflage matter? It is a whole lot better than simply wearing black clothes and
walking slowly.Praxichys - 28-9-2015 at 06:20
@TheAlchemistPirate - I was thinking the same thing.
Covering airplanes with OLED displays that match the background will make them essentially invisible until they're close enough for it not to matter.
As long as you can't see it like 1000 feet away, it will be just fine for combat use.
The thing is, most guided rockets and early detection systems use thermal and radar signatures to track targets. Making a radar-absorbing,
environmentally isothermic and isoluminous OLED display will be challenging. It's kind of moot since no respectable nation these days tracks air
targets by sight.
Ground vehicles could benefit from this to hide them from air attack. As long as the plane has to be within about 1000 feet to detect a vehicle with
the naked eye, the vehicles will be essentially invisible. (Maybe have some air jets to wipe out tire tracks or something, and some way to hide a dust
trail)
However, the problem with thermal and radar detection remains.
I can see this put to good use in helicopters which need to operate in areas where there is an abundance of risk from small arms and RPGs, all of
which are visually aimed. Otherwise, it is better to worry about radar concealment and make it go fast enough or high enough for visual target
acquisition to be ineffective. Little_Ghost_again - 5-10-2015 at 10:08
There is a glass that you can see through from one side and on the other you can words or a picture, its used a fair bit like an autoque for people
talking. Also there is a bank with it on the doors, you see the bank logo on the way in but when inside you can see straight through the glass, its
not mirrored or anything.aga - 5-10-2015 at 11:23
Yeah. It's a one way mirror.
I made one in a bottle instead of Silvering it properly !Pyrovus - 6-10-2015 at 04:21
So called "one way mirrors" actually aren't, they just exploit an illusion to appear that way. The trick is that you get a weak mirror that allows a
lot of light to pass through. Then (imagining the standard police setting), you set up the lighting so that the interrogation room is brightly lit,
and the observation room is dimly lit. From the perspective of someone in the interrogation room, there will be a very small amount of light passing
through the mirror, which will be drowned out by the large amount of light being reflected by it, so as such they will not be able to see into the
room beyond. From the perspective of someone in the observation room, the opposite will be the case - the small amount of light reflected by the
mirror will be drowned out by the large amount passing through it, so they will be able to see into the next room, but they won't be able to see their
reflection in the mirror.franklyn - 8-10-2015 at 05:51
If the glass has a polarized transmission filter allowing light to pass from the room being watched but the light
in the watching room has opposite polarity , nothing can pass into the room being watched.Little_Ghost_again - 8-10-2015 at 10:24
This isnt a mirror, its completely clear, they can them somehow show a frosted type text. I will try and dig around to find what I am on about.
Its way more like a clear LCD screen but not exactly the same, god this is frustrating trying to find something you dont know the name of!
Give it some time and you'll see it on discovery channel eventually
