> Since I am very familiar with the tech, I know that IR light does not have any special properties in detecting a mask vs human skin.
Since you're familiar with the tech, you'll be aware that humans, who are alive, emit IR light which can be picked up by an IR camera, and a mask, which is not, does not.
> Health concerns. It is unclear if an attacker would get his eyes and face skins hurt, under the exposure of such a large amount of infrared in a long period of time. If this is true after confirmation from physicians, attackers may not dare to launch attacks with this method, worrying about their health.
As a physician, I don't understand this to be a serious concern. UV light is the opposite side of the viable spectrum from IR
I don't know much about far infrared, but the 6-7mm penetration in this paper seems deeper than the ~4mm penetration I recall reading about for UCNP-NIR.
> Near-infrared light can go as deep as 10 centimeters (~ 4 inches) into the human body.
This attribute of the infrared light is key to treating cancer anywhere in the human body with this method. As long as the patient is not obese, I assume 10 centimeters of penetration depth are enough to reach any part of the body.
Penetration depth and the precision of the desired effect is something that is very important in radiation therapy as well. With radiation therapy you basically shoot small particles at the cancer cells but you also damage surroundings if you don't aim precisely enough. Dependig on the depth of the cancer cells inside the body, different particles are used. The amount of damage the particles deal depends on physical effects. Photons deal most of the damage on the surface. More heavy particles like alpha particles deal most of the damage once they are slowed down inside the body. (See Bragg peak https://en.wikipedia.org/wiki/Bragg_peak ).
> The next step, more controversial, would be super-vision of tetrachromacity, perhaps infra-red and ultra-violet sensitivity. Night vision glasses no longer needed for enhanced soldiers.
Utter poppycock.
The cornea and lens in humans are UV opaque, which is a very good thing because UV light is damaging. People without a lens (aphakia) are reported to perceive UV light, but this is otherwise an undesirable condition. As to infrared, some people can already see up to around 750nm or so (NIR) with awful quantum efficiency. Pit vipers and some fish have limited perception of IR, but I'm not aware of any animals that can see IR in the conventional sense… being warm blooded presents a real problem, for one.
Plainly, there are limits to what can be achieved in hyperspectral imaging due to materials, and that's without the constraints of biology thrown in the mix.
>people nowadays is using IR cameras without any calibration or understanding of the physics behind the measurement
The four factors are Emissivity (e), Absorptivity (a), reflectivity (?) and transmissivity (t). Emissivity is only one facet. Ideal is high Emissivity and low reflectivity.
> If it was IC, or even high-powered batteries, it would have been hot enough to look like a flare under night vision goggles.
I think you're thinking of thermals, unless it's on fire or something it's not going to emit the NIR/visible spectrum light that would be picked up by night vision.
Thank you. It was an extremely confusing statement.
I would have gone with something like "a wavelength about 7 to 40 times longer than the longest wavelength human eyes can perceive", or "longer wavelengths than a night vision scope picks up, but shorter than most thermal imagers capture or microwave ovens emit". But really, it might make more sense to have just omitted everything after "mid-infrared wavelengths of light". Kind of like the unnecessary use earlier in the article of both parsecs and light-years. Just go with light-years IMO.
Aside I've had chance to read teh article and there was no mention of taking near-IR images at day and night. So presumably it's my language use that's getting me heavily downmodded?
Actually I think you were downmodded for not reading the article and then asking a question that could have been answered by reading the article.
Oh right, i did't think about the penetration depth.
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