RPG Forums

Go Back   RPG Forums > Role Playing Game Section > Archive

Thread Tools Search this Thread Display Modes
Old 01-21-2010, 11:44 PM
kato13's Avatar
kato13 kato13 is online now
Join Date: May 2007
Location: Chicago, Il USA
Posts: 3,664
Send a message via ICQ to kato13
Default Thermal Imagers

kcdusk 11-16-2005, 08:49 PM Aside from being able to see at night (people out to 1500m and vehicles to 3000m) do thermal imagers have any modifiers to observation, in the same way that binoculars are + 1?


pmulcahy 11-17-2005, 12:16 AM Aside from being able to see at night (people out to 1500m and vehicles to 3000m) do thermal imagers have any modifiers to observation, in the same way that binoculars are + 1?

Not that I know of, game-wise.

Now, I'll grant you that my experience with thermal imagers is over a decade old, but unless they have improved, I can tell you this: the image quality at long range (1500m+) is CRAP. You can make out general shapes of vehicles, but they become quite indistinct, and telling what kind of vehicle you are looking at can be difficult. Soldiers on the ground look like little more than points of light. There is a reason there were so many friendly fire incidents in Desert Storm.


Targan 11-17-2005, 12:41 AM I agree with you Paul, unless the target is close all you can tell using Thermal Imagers is that there is a heat source, and it is large, small, difuse, compact, warm or very hot. In my campaign there have been hundreds of contacts registered by my players' characters using TI equipment, which have triggered clearing patrols or counter ambush drills but turned out to be nothing of any consequence.

One interesting use for TI equipment in RL is that airport saff have been using it to scan incoming international travellers to see if they have an elevated body temperature, a possible sign of infection from, say, Avian Influenza.

As I understand it, TI gear can only see through walls if the wall is thin and not a great insulator, or if someone/something warm has been in contact with the wall's surface on the other side for quite some time (say, someone sitting with his back to a wall, or sleeping at the edge of a room).

I am assuming something hot and in the open like a big campfire or a factory smokestack would produce a visible plume of hot air rising into the sky. That could be useful if a group is trying to determine whether a site is currently inhabited.

Possibly TI gear could also be sensitive enough to detect heat generated by electrical systems in wiring, allowing the user to determine if a given cable has current flowing through it.


ReHerakhte 11-17-2005, 06:08 AM To add to what Paul & Targan mentioned, thermal imagers can be used in quite a few ways that aren't immediately thought of. I'm not talking about the specialized units such as thermal imaging thermometers used for medical/technical use either but your standard military or civilian type thermal imager (especially if you have the nifty new handhelds that look like mini-video cameras!)

In relation to Targan's comments, some fire brigades use them to gauge the heat intensity of possible building fires particularly if there is little obvious sign of a fire. They also use them in the traditional sense of seeing through smoke etc. and also for checking places to ensure the heat has been reduced.

Freshly dug earth will give off a different temperature than dirt that has been undisturbed, a TI will detect the difference (they have been used in former Yugloslavia for the detection of mass graves and the US police use this method to look for backyard caches).

In a somewhat similar manner, they can be used to detect the difference in a solid wall and a part of the wall that may be hollow (as in a hidden compartment) by the temperature difference. And this technique is also used for detecting hollow areas under snow.

Modern imagers are sensitive enough to pick up even minor temperature variations in electrical gear as Targan suggested. In this manner they are being used to detect overloads in electrical switchboards or poor connections on circuit boards.

US police officers have found that TIs will detect skid marks from accident/crime scenes due to the thermal differences due to the tyre rubber being left on the road, even if someone had tried to scrub the skid marks off the road surface!

Pollutants such as oils and chemicals have different thermal properties to the ground and so can not only be detected, but if they have flowed along the ground or been spilt, they can be traced back to their source. This is also effective in water apparently.

Colour versions are being used in the building trade to detect badly sealed wall/wall and wall/floor or wall/roof edges as the airflow passing through the gaps shows up cooler than the building material.

And here's one you guys might like, well, your Players might! At night, the medic can't necessarily tell if or where someone is bleeding without appropriate lighting, a thermal imager can detect the presence of blood in poor light, again due to the difference in temperature between it and the surrounding material (be it clothing, skin etc.) US police officers have found that even if blood has been hastily cleaned off walls or floors, enough of it remains to cause a temperature difference so that its presence can be detected (you won't know specifically that it is blood, but you'll know some was on the wall/floor that doesn't match the rest of the panel).

And to add to what Paul was saying, manufacturers typically talk about thermal imager ranges as Detection, Recognition and Identification ranges. Basically, you might be able to Detect a large vehicle with a TI at, for example, 20km but you won't Recognize it until it is within about half that range (i.e. about 10km). You won't be able to Identify the specific type & model until it is even closer which is about half the Recognition range (i.e. 5km). A large vehicle is presumed to be tank size, roughly 8 metres or so in length, small vehicles are presumed to be about 2 metres or so in length and their ranges are typically half of that given for large vehicles.

So even if it does detect large vehicles out to 20km, you're not going to know what type of vehicle it is until it's at 10km and you're not going to be able to specifically identify it until its at 5km.

Smaller imagers typically have ranges of up to 10km for large vehicles so the example mentioned in Twilight should be taken as a late-1980s model (with small thermal waveband discrimination) rather than a mid-1990s model (with a broader thermal waveband discrimination).

All these ranges presume a clear line of sight to the vehicle with good weather. Like the book says, fog, rain, smoke will dimish these ranges. In poor conditions, your 20km detection range is down to about 5km at which range you can still identift it as friend or foe.

Detecting personnel is typically a quarter of the Dection, Recognition & Identification ranges given for large vehicles (i.e. about 4-5km) but due to the target being nearer, weather effects don't diminish the image and recognition and even identification can occur at 4km regardless of most weather

Colour, handheld, non-cooled thermal imaging technology has been in use since the mid-1990s so it was therefore being worked on in the late-1980s/early-1990s... which means it is not out of place in Twilight, you just won't have many of them!

As for any bonus to Observation... you probably don't need one, you can't hide from Thermal... they see in total darkness, rescuers use them for locating people lost in snow, oceans, forests etc, police use them for locating criminals hiding in bushes, forests, under snow, under sheets of tin or plywood etc. The more sensitive (as in better discrimination between wavelengths) versions will detect the heat rising from people hiding behind walls or in dead ground and they detect the heat rising from smoke stacks, campfires etc.

However - if you don't look in the right direction, you're not going to see what you're looking for (which is a really crappy answer I know)

And this is quite long enough so I'll stop my dribbling!




thefusilier 11-17-2005, 06:32 AM Anyone ever take into account for their game that a number of these... especially the ones that would be used in Tw2000 (not the ones out now in real life) make quite a bit of noise.

We had a bunch of international ones out for comparrison demonstration. Some were loud, some not. The one I mostly used in the Canadian army was an older model we called a NOD or NODDLER. I could see a tank at nearly 4000m but it was one of the noisier ones.


Targan 11-17-2005, 06:40 AM I suspect some of the older units may be quite resistant to EMP. I wonder, do the noisier units tend to use more power?


thefusilier 11-17-2005, 06:51 AM I'm not sure about either of those questions. But remember EMP only really damages equipment turned on... and is only really created effectively if the blast is waay up in the atmosphere. Because much of EMP from nukes is not really too understood 100%, would either side risk trying to create EMP in Europe... it could easily affect their own forces. Some tests had effects going out 800km. Detonating a nuke over the US or the USSR dosn't create the problem of hitting ones own electronics.

Thinking back again... I suspect those noisier ones did use more power. But then again its only a guess.


kcdusk 11-17-2005, 01:35 PM TI's, i thought they were hand held like binoculars?

Also, your saying as long as you look in the right direction, observation is "automatic"?

Some good alternative ideas there also. As for picking up bleeders though, I aint got time to bleed!


ReHerakhte 11-17-2005, 04:41 PM TI's, i thought they were hand held like binoculars?

There are a number of different types, the earliest models in use with the military were often large boxy things mounted on a tripod using up plenty of power and requiring something like liquid nitrogen to keep their sensors super-cooled so they could pick up even the smallest amount of heat difference. The one I got to play around with in the Aussie Army was like this and speaking of noise I do vaguely recall a high pitched whine from the thing, kinda like a mosquito.

Smaller versions were also made for infantry use and these were either like outsized Starlight scopes for fitting to weapons or bulky binoculars for handheld use. These types used other methods for keeping the sensors cooled and so you didn't have the worry of lugging around a bottle of liquid nitrogen!

Later versions (early-1990s) introduced sensors that didn't require cooling and in some models, colour screens. Most modern versions are also quite often, lightweight handheld models looking very much like a mini-videocamera. I was trying to convince my boss we needed one of these for work just so I could play around with one.

The type of uses that you can put it to include all the stuff I mentioned earlier but I forgot the following: - detecting liquid levels in tanks or containers (as the denser liquid gives off a different thermal signiture to the air filled portion) and detecting injury sites under the skin (typically because an injury site generates more heat than uninjured areas as the body tries to repair the damage).

The very latest models are literally digital cameras using colour and black & white thermal imaging and will record the objects you have been viewing so you can review them or dump them into a computer for further analysis.

Also, there are companies now who repackage TI electronics into smaller devices, for example, some US companies use the AN/PVS-7 Starlight goggles, ripping out the Starlight electronics and replacing it with TI. Check out the following for just one company that does this http://www.imaging1.com/thermal/infrared%20goggles.html

Also, your saying as long as you look in the right direction, observation is "automatic"?

Thermal Imagers work on external light reflected off an object but more importantly, the heat radiated by an object. If you have line of sight to someone, you will see them with the TI, their body heat betrays them. And by line of sight I mean that they aren't hidden behind buildings, hills etc.

Even if they are hiding behind thick bushes, under 50cm of snow or behind a wall, they will generate heat and this heat will cause a difference at (or above - heat rises) the spot they're hiding compared to the surroundings.

Even the F-117 "Stealth Fighter" can't hide from thermal imaging when it's flying because the air passing over its body causes friction which causes heat but more importantly, its engines simpy generate too much heat for it to hide.

When it comes to using them, the real trick is that although you will see the heat difference, will you know what it is? If someone hides under a car, you will see more heat being given off from under the car but would you recognize it as something unusual, would you recognize it as the heat given off by a person, or a small animal such as a dog etc.

If someone hides behind a thick stone wall, you won't notice the tiny change in heat of the stones they are in bodily contact with but you will see a slightly warmer patch of air above where they are hiding. How will you know if this is just some warm air being blown out of a sewer vent, a trashcan fire or a person lying in wait with an RPG?

Or is it just background heat from an object in the distance such as another building or a granite rock outcrop etc.

The answer all comes down to training. If people get the training to recognize these things, they will generally be correct in their identifications but they need at least basic training in thermal imaging use to be able to recognize the different types of heat given off by people, animals, buildings, vehicles etc when they are in the open, behind objects, operating/not operating etc.

So yes you could say Observation is automatic if they are looking at the object... automatic for the imager that is, people still need to blink (and they might blink at the wrong time) and as mentioned in the blurb above, they still need to understand exactly what it is they are looking at, they might see it but fail to understand what it is and therefore won't know what its significance is. So in a game sense I think it's very much worth making an Observation roll, the imager will pick up the heat difference but the character still has to understand what they are seeing. With training or experience, you could just lower the difficulty level of the Observation task.

I hadn't really thought much about that in my own games as no-one ever used a thermal imager but I think I will use this method myself.

Sorry for more lengthy dribbling about this subject, I go into long explanations because tend to write what I am thinking at the time instead of coming up with a concise version!




ReHerakhte 11-17-2005, 04:48 PM Something else I forgot to mention... (sorry, here I go again!)

Uncooled TIs operate at room temperature and the electronics are completely quiet. They also benefit from immediate activation, you switch it on and it's ready to go straight away.

Cooled TIs use cryogenic cooling (e.g. liquid nitrogen), they are naturally more susceptible to damage because the sensors are contained in a package that keeps them at a temp of less than 0 degress C. Their benefit is that they can detect a heat difference of 0.1 degree C at up to 300m away. These types generally have much longer ranges than uncooled types and are the version most often used by the military in aircraft & vehicle weapon systems.

However, range can be increased on a TI by the simple expedient of fitting a magnifying lens and some companies offer detachable lenses for this purpose.

(Surprisingly short reply this time!)




Targan 11-17-2005, 11:09 PM In response to thefusillier, I have a US military PDF outlining the known effects of EMP, and it says EMP affects many electrical and electronic systems whether they are switched on or not. The damage would likely be more severe if the device was turned on, but unshielded microchips, for example, are pretty vulnerable even if not operating. You can generate EM pulses in more ways than just high altitude nuclear detonations, but nukes make the most powerful artificial EMPs.

My question about whether older TI devices were more resistant to EMP was prompted by my suspicion that they may contain more transistors than modern gear, or even maybe vacuum tubes, which are highly resistant to EMP.


ReHerakhte 11-18-2005, 03:43 AM G'Day all,

A while back there was a thread discussing EMP and I mentioned some stuff from a "The Morrow Project" forum where one of the members stated that he was involved in some manner with testing electronics for EMP resistance or some such.

As I recall it, he claimed that any item that is disconnected from a power source would be protected from EMP (even if it is switched off but still connected to a battery or mains power, it's gonna fry).

Apparently transistors are slightly more resistant to EMP than integrated circuits but not enough to really protect them. However, it has also been mentioned in other places that vacuum tubes are very resistant to EMP. This sparked some concern in NATO intelligence circles at one point because after a Russian pilot defected from the Soviet AF to Japan, they examined the MiG-25 he kindly donated to US forces there.

It was found to be using vacuum tubes for most of its electronics. The NATO honchos started to worry that the Sovs where using tubes to help them ride out the EMP as part of their preparation for nuclear war with the West.

As it turns out, the MiG-25 was using tubes because Soviet technology was something like 20 years behind the West!




Targan 11-18-2005, 03:58 AM Yup, right on. That Mig 25 story was where I first learned about the EMP resistance of vacuum tubes. My understanding is that EMP induces current through any circuit (or near-circuit, if the induced current is strong enough to arc), but the greater the distance from one end of the circuit to the other, the higher the induced charge. That is why anything connected to mains power is vulnerable, because the currents induced through large scale electrical nets by EMP could get pretty big! But if the EMP is powerful enough, sensitive electronic devices with even tiny components can still have sufficient current induced to cause damage or destruction, even if switched off and independently powered. Electronic fuel injection or even automotive coils can easily become victims to induced charge if exposed to EMP. There are other indirect types of potential damage from EMP which I can't remember clearly, and from nukes in general there can be other problems such as ionising hard radiation.


thefusilier 11-18-2005, 08:49 PM Sorry for potential sending out misinformation on the EMP. I said "EMP only really damages equipment turned on...". What I was infering is what you mentioned, turned off can still be affected... but the effects and chances of such are much less. Yes unplugging further protects it. One of the drills for immenant nuc strike (at least for ground units) we used to do was protect certain gear we had (I saw this once when I happened to be at a comms and int. unit).


O'Borg 11-22-2005, 09:48 AM As I understand it, TI gear can only see through walls if the wall is thin and not a great insulator, or if someone/something warm has been in contact with the wall's surface on the other side for quite some time (say, someone sitting with his back to a wall, or sleeping at the edge of a room).

Possibly TI gear could also be sensitive enough to detect heat generated by electrical systems in wiring, allowing the user to determine if a given cable has current flowing through it.

In my youth I served an electronics apprenticeship for a large defense contractor who supplied ship/aircraft mounted thermal imaging cameras to the military & police.

The 'see through walls' business is a bit of a misnomer as Targan says. I remember seeing myself on camera several times and my spectacles became dark glasses every time, even though the lenses were plastic not glass.

Glass itself is particularly opaque to IR, if you ever watch one of those Police Camera shows where the helicopter tracks the suspects using a thermal imaging camera, glasshouses invariably show up as a solid block of black, although localised heat will show through.

As for the wiring, where I worked one of the 'show' pictures in the reception area was a thermal image of a normal saloon car with black hot/white cold.

You could clearly see the lines of the heated rear windscreen showing up black.

I never saw it myself, but a popular trick some of the guys in the test area would play on the apprentices was to point an IR camera on them as they came out of the toilets, because you could see who had dribbled a bit...


pmulcahy 11-22-2005, 06:49 PM When I was in the Army, there was a rumor I was never able to prove or disprove: That on thermal imagers or Infrared devices (not light-intensification devices, like most NODs are these days), that you can actually see someone fart. Anybody know if that one is true?


kcdusk 11-22-2005, 07:20 PM I cant answer your um, technical question PM, but perhaps a question just as relevant as yours.

TI's wont work during the day, will they? Would they blind a PC or would everything just show as hot?


pmulcahy 11-22-2005, 11:01 PM I honestly never tried the thermal imager on the Bradley during the day; it has an excellent image intensifier. And you don't use NODs in the daytime, because you will be blinded, and burn out the NODs to boot.


ReHerakhte 11-23-2005, 01:58 AM In short, Yes, they can be used during the day.

As mentioned by Paul, night observation devices can not be used during the day because they use light amplification, you give them too much light and you'll blind them. For example, I used the AN/PVS-4 night weapons sight quite a bit and generally it is still a decent system even today but being an older generation of starlight devices, if you get too close to the ground, even the grass reflects back enough light to cause some "white-out" of the image.

Thermal imagers don't need to amplify light to enhance the image because they measure the temperature variation of an object and present an image based upon that.

For a general overview of thermal imaging technology and its uses, check the following: -





thefusilier 11-23-2005, 03:21 AM The Canadian Lav-25 (an improved version) has a nice set inside for the infantry section to use as well as for the crew. You can access the gun camera, commanders camera and the front facing camera all on the screen. It works perfect in the daytime and will not blind out. It has the usual option of hot > white or hot > black. Or you can simple switch to CCTV.


Last edited by kato13; 02-09-2010 at 12:24 AM.
Reply With Quote


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -6. The time now is 08:03 PM.

Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.