Thermographic Sensors

[Serious Paul]

Can anyone give me an idea of just how accurate thermographic sensors currently are? Also what sort of limitations would they have? How would you hide from thermographic sensors?

I think i know the answers but I'm looking to what I think coincides with reality and what others imagine.

[Bonefish]

Goddamned accurate, is what I hear. After-all, if you've ever seen the guncam footage from an AC-130, bombing the shit out of the taliban in Afghanistan? That's a themographic sensor.

Glass, apparently, is Opaque to them, as are mirrors. Telling someone apart from another person though could be different if they are similar sized and shaped.

[3278]

Can anyone give me an idea of just how accurate thermographic sensors currently are?

Very. FLIR makes some goods ones, and they've got an image gallery that gives a good idea of what they can do. It's genuinely pretty close to visual light, now, but of course it's limited to heat.

Also what sort of limitations would they have?

Anything that'll stop heat will stop IR, like double-paned glass. Some modern MWIR can see through single-paned glass, though with a reduction in efficiency.

How would you hide from thermographic sensors?

Just like visible light, you have to look like what's behind you. You can camouflage yourself by breaking up the outline of your pattern, for example. You can make yourself the same "color" - read: temperature - as what's behind you. But all of this requires that you can keep your own temperature in, because the difference between IR and visible light, when it comes to people, is that we don't glow in visual light.

All that said, in any kind of "looking for people" role, there's likely to be a visual /and/ an IR camera, meaning you've got to hide from both, which is going to be very difficult.

[Serious Paul]

Let me run a specific scenario by you guys-wait I already know the answer. I'll explain it tomorrow 32. You'll laugh.

[paladin2019]

If this is a SR specific question, the answer changes a bit.

Current IR/FLIR/Near IR technologies are monochrome, probably because the monitors are cheaper. SR thermographs are not. Why does it matter? With a monochrome viewer, you have one axis for differentiation. But a thermograph can determine temperature and "brightness" separately. In other words, since a fire can simply be brighter, the rendering of the fire can be differentiated from what's around it through color rather than the image processing just washing the scene out.

As for current IR performance, properly camouflage patterns show up. Yep, old school woodland camo is visible as monochrome woodland camo in good imagers. Also, trees and such have their own heat signatures.

Understand that the goal of current IR technologies is more to seeas well in darkness as daylight rather than to see heat. Imagers are designed thusly. Therefore, the same stealth techniques generally apply. Camouflage and other methods of concealment (vs cover) are less useful and your mistakes are simply amplified. For gaming rules, I'd rule that under a certain margin of success or dependent on environmental conditions, you give observers/searchers a significant bonus to their spotting chances.

For example, in SRe and earlier if your open test doesn't beat the IR sensor's rating (use Intelligence for cyber/natural), the result is halved.

[3278]

Current IR/FLIR/Near IR technologies are monochrome, probably because the monitors are cheaper.

I'm not sure what you mean. Could you explain?

SR thermographs are not. Why does it matter? With a monochrome viewer, you have one axis for differentiation. But a thermograph can determine temperature and "brightness" separately.

I'm not sure what you mean. Could you explain?

Understand that the goal of current IR technologies is more to seeas well in darkness as daylight rather than to see heat.

Yeah, the other stuff I could maybe see I'm misunderstanding you, but this just isn't so. There are IR technologies intended for night-vision, and there are IT technologies for temperature analysis. Current technology isn't more for one than another; they each exist, and are both semi-broadly used.

By the way, those curious about the bleeding edge in night vision should check this out.

[paladin2019]

Current IR/FLIR/Near IR technologies are monochrome, probably because the monitors are cheaper.

I'm not sure what you mean. Could you explain?

The output is monochrome, shades of black/white, green or red. My guess is simplified image processing and cheaper displays.

SR thermographs are not. Why does it matter? With a monochrome viewer, you have one axis for differentiation. But a thermograph can determine temperature and "brightness" separately.

I'm not sure what you mean. Could you explain?

Forget everything I said, I think I either confused another game's definitions or this distinction is buried in a supplement I'm too lazy to dig for.

Or don't. If you can diferentiate temperature by color (hot is red, cold is blue, etc) then brightness can be a separate discriminator in the image and can help with flare comp. If hot doesn't have to be "white" then a campfire doesn't necessarily have to mask the guys partying behind it. It can be the red thing in the foreground and the guys are the yellow things behind it. And if you can do facial recognition with a PVS-5....

[Serious Paul]

Bad karma sent this link to me today. Very convenient.

[3278]

Current IR/FLIR/Near IR technologies are monochrome, probably because the monitors are cheaper.

I'm not sure what you mean. Could you explain?

The output is monochrome, shades of black/white, green or red. My guess is simplified image processing and cheaper displays.

IR output isn't necessarily monochrome. It can be - I don't know if it's because of display cheapness, or improved contrast, or better night vision - but they aren't necessarily. It seems like the military / police systems typically are, while the civilian / engineering / science ones are in false-color.

[Serious Paul]

Okay question: Trees can only absorb so much of the ambient temperature, even in a tropical jungle right? So one could pretty readily tell the difference between the tree and the backdrop right? Or wrong?

[paladin2019]

Okay question: Trees can only absorb so much of the ambient temperature, even in a tropical jungle right? So one could pretty readily tell the difference between the tree and the backdrop right? Or wrong?

I've never had a problem with trees. They have always shown up as hot, too.

[3278]

Okay question: Trees can only absorb so much of the ambient temperature, even in a tropical jungle right?

Well, the tree will still seek equilibrium with its environment, so if you held it at 100 degrees, they'd eventually hit 100 degrees. But just like a lake holds it coolness during the day, and keeps some warmth at night, there's going to be lag between temperature changes and the response of the tree: in the morning, the tree will be cooler than the surrounding air for a while, but at night, they'll be warmer for a bit. It's their water content, more than the wood itself, that acts like a big heat sink in this way.