Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: laserman on 10/07/2006 01:04:50
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I found a crazy guy selling what appears to be infrared glasses and flourescent dye. I think that these could be what can use long near infrared to pass through certain types of clothing
http://stores.ebay.com/Kinetic-red-technologies
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Depends upon what you mean by seeing through clothing.
X-rays can generally see through clothing (unless you are wearing a metal suite of armour), but they will also see through much of the soft tissue of your body.
The heat given off by the human body is in the far IR, and will not be visible in the near IR.
Nonetheless, IR photography (which is generally in the near IR) can have some interesting effects, but it will not generally see through clothing (although I understand that dark sunglasses become transparent to near IR, but ordinary vegetation does not, so I would doubt that cotton clothing would become transparent. I cannot say how thin nylon, or other polymer based clothing would react to near IR, but most clothing I suspect would remain opaque).
George
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Millimeter and sub millimeter waves see through clothing but you need special (and quite large) equipment and fancy signal processing to form the image. They are used in in very advanced security systems to identify hidden weapons at shortish ranges. there is also a high power version which is a non lethal weapon that heats the skin surface and gives an intense burning sensation that has been propsed as an alternative to water cannons in driving back rioting crowds.
As to whether that kit works I somewhat doubt it because the site has been closed :-)
Learn, create, test and tell
evolution rules in all things
God says so!
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While infrared video cameras (like 900nM wavelength) can certainly see through a particular kind of cloth, there is no evidence that human eyes can do the same. The sensitivity of human eyes goes way down above 700nM, and *way* down when above 750nM.
Here are some photos shot with infrared video cameras:
http://www.kaya-optics.com/products/experiments.shtml
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Re: seeing thru cloth.
It was ages ago, I saw this TV program on the BBC called Tonight (I think) and they had this bloke who could see thru cloth. He did relatively well in their test, seeing a figure which actually turned out to be a figure on a vase. When presented with a cardboard box with an object in it, he immediately said that he couldn't see thru cardboard.
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Re: seeing thru cloth.
It was ages ago, I saw this TV program on the BBC called Tonight (I think) and they had this bloke who could see thru cloth. He did relatively well in their test, seeing a figure which actually turned out to be a figure on a vase. When presented with a cardboard box with an object in it, he immediately said that he couldn't see thru cardboard.
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I am sure I too have also seen a camera that can see through clothing but it's not the result you might be expecting ie: to appear to make people nude (though...from a deviants point of view I'd buy some if they existed [;)])
It displays an image akin (but not identical) to an x-ray with outlines and shadows along the grey scale.
Men are the same as women, just inside out !
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If we do not see through a coton fabric it is not so much because light does not pas through. We see it as white because light is diffracted in all directions, due to the difference in refractive index between the fibre and the surrounding air.
A glass plate (thick or thin, it soes not matter) can be seen through because it is a homogenous body, but a fibreglass mat is more opaque because we have fibres and aird between, with a high difference in refractive index.
The reason why we see through a wet t-shirt is that the difference in refractive index between the fibre and water is much lower than the difference between the fibre and air. And it is for the same reason that we do not see through a mist or fog, but we can see through a mass of water.