Improved IR Image (TGP IR)

[Pyroflash]

Having taken three chem courses, I have been taught that heat is a form of energy that describes the overall motion of particles. The reason things like exothermic reactions can produce heat is that potential energy within the bonds are being transformed into thermal energy and then transferred to a particle or system of lower thermal energy.

 

To be clear, thermal energy differs from other forms of energy in which the base velocity of a heated particle is accelerated above what it was previously. A particle in motion which has another form of energy, say kinetic for example, is really the progenitor of heat, because the individual particles that make up the whole of the system are moving and therefore the system has a certain amount of heat(I hate talking about heat like it is made up of a bunch of Caloric, but I am too tired to describe it as the massless energy dependent system that it is). A similar result occurs with potential energy where the particle either has energy stored within its bonds, or has another system acting upon it e.g. gravity. Therefore potential energy is just that, the potential for a particle or system of particles to have energy.

 

It is possible to stop a particle's motion inside a system(with current technology, we can come close seen in Bose-Einstein Condensates), by cooling it to absolute zero. t that point, the random motion of particles will have completely stopped, and therefore no heat will be contained within the system.

Edited March 15, 2011 by Pyroflash

[Sticky]

Having taken three chem courses, I have been taught that heat is a form of energy that describes the overall motion of particles.

 

Then you were taught wrong, but more likely remember it wrong. I have probably over fifteen chemistry courses on university level, and I can tell you thats NOT what heat is.

 

"Heat is the transfer of energy between two bodies that are at different temperatures. Like work, heat appears only at the boundary of the system and is defined by a process. Energy is transferred from a hotter object to a colder one because there is a temperature difference. Heat is not a property of a system and is not a state function." - Taken directly from my old course materials, yeah you guys forced me to bring that shit out again lol :megalol:

[Zenra]

Have to agree with Sticky here, but to bring this back around to the original topic it is important to understand that it does not matter how much internal energy a body of mass has or how “hot” it is, unless it is radiating energy in the form of infrared light the TGP cannot see it.

 

I’ve taken many chemistry, thermodynamics and heat transfer courses obtaining two engineering degrees, and my day job is designing surgical navigation systems that employ infrared LEDs to track surgical instruments relative to the patient’s anatomy as part of a larger computer-assisted surgical system. We use infrared emitters for many of the same reasons that working in the infrared part of the spectrum benefits detecting targets on the battlefield, including:

 

1. Infrared light is relatively immune to interference from light in the visual part of the spectrum as well as other forms of emitted electromagnetic energy

2. Infrared light can be seen through many materials that obscure or block light in the visible part of the spectrum (e.g., water vapor)

3. Its wavelength is very short compared with emitted energy such as radio waves and therefore can be detected using very small sensors (as opposed to such things as antennae used to detect radio waves) and so offers excellent resolution for visual imaging

[Mule]

this thread turned into BBC 2

[Pyroflash]

Then you were taught wrong, but more likely remember it wrong. I have probably over fifteen chemistry courses on university level, and I can tell you thats NOT what heat is.

 

"Heat is the transfer of energy between two bodies that are at different temperatures. Like work, heat appears only at the boundary of the system and is defined by a process. Energy is transferred from a hotter object to a colder one because there is a temperature difference. Heat is not a property of a system and is not a state function." - Taken directly from my old course materials, yeah you guys forced me to bring that shit out again lol :megalol:

 

15 chem courses? What do you do for a living(just curious)?

[bumfire]

15 chem courses? What do you do for a living(just curious)?

 

Bus Driver :lol:

[VincentLaw]

"IR" is an acronym for "Infrared Radiation". Radiative heat transfer is one of the three classic forms of heat transfer, which are Conductive, Radiative, and Convective (although the latter is really a combination of Conductive heat transfer and mass transfer rather than a truly unique heat thransfer mechanism).

 

I have also taken a course on Thermodynamics, and this is a good description by Zenra. Heat is simply the transfer of energy between an object and its surroundings, so IR is heat, but heat does not equal IR (unless you are in a vacuum and there is no other radiation). Since heat can also occur from conduction and convection, a hypothetical system A can actually have more heat but less IR than system B.

 

Having taken three chem courses, I have been taught that heat is a form of energy that describes the overall motion of particles.

 

This is just temperature, not heat.

Edited March 16, 2011 by VincentLaw

[BiPod]

Gawd! The universtity system has a lot to answer for. So many people with qualifications and no concensus on one of the most basic principles in science!

 

I was shaking my head in dismay until I found this:

 

 

 

Wikipedia - "Heat"

Semantic misconceptions

 

There is some debate in the scientific community regarding exactly how the term heat should be used.[11] In current scientific usage, the language surrounding the term can be conflicting and even misleading. One study showed that several popular textbooks used language that implied several meanings of the term, that heat is the process of transferring energy, that it is the transferred energy, i.e., as if it were a substance, and that is an entity contained within a system, among other similar descriptions. The study determined it was not uncommon for a combination of these representations to appear within the same text.[12] They found the predominant use among physicists to be that if it were a substance.

 

In a 2004 lecture, Friedrich Herrmann mentioned that the confusion may result from the modern practice of defining heat in terms of energy, which is at odds both with the historic scientific definitions and with the modern lay concept of heat. He argues that the quantity heat as introduced by Joseph Black in the 18th century, and as used extensively by Sadi Carnot, was in fact what is today known as entropy-- something possessed by a substance in amounts related to that substance's temperature and mass, which exits one substance and enters another in the presence of a temperature gradient and can be created in many ways but never destroyed. He further argues that the layperson's concept of heat is also essentially this entropy concept, and so in re-defining heat to refer to an energy concept, modern science creates an unnecessarily awkward and confusing presentation of thermal physics. [13]

 

 

 

 

It seems there is more than one definition of heat in use, and this seems to be to cause of the bunfight that this thread has become:). Several of the posts above are completely correct even though they contradict other correct posts.

 

For the record, I use the substance definition of heat which is the "predominant use among physicists". VincentLaw is using the transfer definition which is apparently the original definition and the one used by Wikipedia.

 

BiPod.

[Sticky]

The transfer definition is what you will HAVE TO use if you are a chemical engineer, otherwise you will screw things up :) I dont know about other fields, I was sure it was the same for all engineers. Anything that uses heat in any calculations would have to use the "correct" transfer definitions, otherwise the math will be all wrong. Wrong math = potential catastrophy :)

Edited March 16, 2011 by Sticky

[Sticky]

Gawd! The universtity system has a lot to answer for. So many people with qualifications and no concensus on one of the most basic principles in science!

 

I was shaking my head in dismay until I found this:

 

 

 

Wikipedia - "Heat"

Semantic misconceptions

 

There is some debate in the scientific community regarding exactly how the term heat should be used.[11] In current scientific usage, the language surrounding the term can be conflicting and even misleading. One study showed that several popular textbooks used language that implied several meanings of the term, that heat is the process of transferring energy, that it is the transferred energy, i.e., as if it were a substance, and that is an entity contained within a system, among other similar descriptions. The study determined it was not uncommon for a combination of these representations to appear within the same text.[12] They found the predominant use among physicists to be that if it were a substance.

 

In a 2004 lecture, Friedrich Herrmann mentioned that the confusion may result from the modern practice of defining heat in terms of energy, which is at odds both with the historic scientific definitions and with the modern lay concept of heat. He argues that the quantity heat as introduced by Joseph Black in the 18th century, and as used extensively by Sadi Carnot, was in fact what is today known as entropy-- something possessed by a substance in amounts related to that substance's temperature and mass, which exits one substance and enters another in the presence of a temperature gradient and can be created in many ways but never destroyed. He further argues that the layperson's concept of heat is also essentially this entropy concept, and so in re-defining heat to refer to an energy concept, modern science creates an unnecessarily awkward and confusing presentation of thermal physics. [13]

 

 

 

 

It seems there is more than one definition of heat in use, and this seems to be to cause of the bunfight that this thread has become:). Several of the posts above are completely correct even though they contradict other correct posts.

 

For the record, I use the substance definition of heat which is the "predominant use among physicists". VincentLaw is using the transfer definition which is apparently the original definition and the one used by Wikipedia.

 

BiPod.

 

I was surprised that they would say that the transfer definition was not the most common among physicists.. I thought, Oh well, its wikipedia. But I looked again :) I think you misunderstood the text you linked, I think with what they called "the substance" definition they mean the "transfer" definition. So they are saying that the transfer definiton is the most common. When they say substance they mean the energy as a substance that can be transferred, they mean the transfer of heat as a substance. Very silly of them to use those words IMO.

 

Im still pretty sure that the transfer definition is the only one that counts for engineers, and if you try to use anything else in your work you will cause alot of trouble.

[Sticky]

Here, I cut this out from the text you had linked: "...that it is the transferred energy, i.e., as if it were a substance .." notice the i.e. :)

[asparagin]

You guys remind me of:

 

 

PS: This is wrong:

 

Then what about exothermic chemical reactions? They produce heat by breaking/creating of chemical bounds. Not by particles bumping into each other.

Edited March 16, 2011 by asparagin

[Sticky]

Is this a definition we can all agree on? :megalol:

 

[Juuba]

RE: above:

If the definition is:

The best firefight audios in a movie: HEAT

 

Then : Yes.

[BiPod]

I was surprised that they would say that the transfer definition was not the most common among physicists.. I thought, Oh well, its wikipedia. But I looked again :) I think you misunderstood the text you linked, I think with what they called "the substance" definition they mean the "transfer" definition. So they are saying that the transfer definiton is the most common. When they say substance they mean the energy as a substance that can be transferred, they mean the transfer of heat as a substance. Very silly of them to use those words IMO.

 

Im still pretty sure that the transfer definition is the only one that counts for engineers, and if you try to use anything else in your work you will cause alot of trouble.

 

Arrrgh!!! I was hoping to stop the bunfight I created. Looks like I just started a new one;). This is now a side issue of a side issue! I hope we can still be friends when this is all over:).

 

I didn't so much misunderstand what they had written as misuse it.

 

I should not have made a distinction between a "transfer" and a "substance" definition. I created a false dichotomy which they did not really imply. The transfer and substance concepts can happily sit together. Just ignore the final sentence in my last post, it was wrong.

 

However, it wasn't silly of them to use those words. That is definitely the way I was taught to view it in physics at Uni. We treat heat as a substance to aid in understanding, but know it is only an abstract concept. This does not mean that physicists and engineers are using incompatable definitions, but perhaps there are differences in the way it is taught.

 

Hoping this is the end of it,

BiPod

Edited March 16, 2011 by BiPod
Typo

[Sticky]

Arrrgh!!! I was hoping to stop the bunfight I created. Looks like I just started a new one;). This is now a side issue of a side issue! I hope we can still be friends when this is all over:).

 

I didn't so much misunderstand what they had written as misuse it.

 

I should not have made a distinction between a "transfer" and a "substance" definition. I created a false dichotomy which they did not really imply. The transfer and substance concepts can happily sit together. Just ignore the final sentence in my last post, it was wrong.

 

However, it wasn't silly of them to use those words. That is definitely the way I was taught to view it in physics at Uni. We treat heat as a substance to aid in understanding, but know it is only an abstract concept. This does not mean that physicists and engineers are using incompatable definitions, but perhaps there are differences in the way it is taught.

 

Hoping this is the end of it,

BiPod

 

Ok I get it, that within the transfer definition there can be two views (transfer of energy vs transfer of energy as a substance). I thought that you used the quote to prove that the everyday molecular motion explanation was the most common among physicists, im sorry, my misunderstanding :) But to make clear my own point: I dont care that there is within the transfer definition two different views, if one of them is the most common then that still supports what I have been saying all along, that heat is not the molecular dancing description that many others gave. To me the transfer of energy and the transfer of energy as a substance were on the same side of the argument, since I wasnt discussing differences within the transfer definitions. I was discussing heat as transfer vs heat as molecular motion. But It was my fault for misunderstanding what you tried to say there :)

 

Hoping this is the end of it,

BiPod

 

Yes please, its getting ridiculous, not fun anymore :D

[Pikey]

Stand back, i can handle this:

 

HEAT (definition)

About 12 years ago I was on holiday in Cyprus. We visited an semi-active volcano and went down into the crater to find lots of holes spouting steam.

 

My girlfriend at the time put her hand in one and immediately jumped up and screamed shouting, "It's hot, it's hot".

 

I looked at her with my best pitiful look in front on the rest of the bus party and said, "You just stuck your hand into a volcano and you are surprised it was hot?"

 

Her face went BRIGHT RED.

 

That's Heat.

[GGTharos]

^^^^

 

The above story is not a real event. The poster is still breathing ;)

[Prophet]

Look what I started :D

[stormrider]

For me FLIR just need some fine-tunning.

 

At 1:30 on that video you can see the trees, but only the trees outline, there's no 'texture' in them. On DCS the trees texture is very visible and sharp, it could look more like in the video by simply being blurred or of lower resolution. Another thing is making all trees of the same light levels, on this screenshot some are white others black.

 

As a photographer, I can say that for me, this image is not FLIR. Its is a Highly contrasted BW image, more like the result of a Light Intensifier Camera.

 

And more than that. Trees dont have heat of their own like mammals, so they would be at the same temperature as the enviroment that surrounds it. And one last thing. If that wasnt enough, that Hummvee has a very uniform heat signature. In real life, the engine bay would be hotter that its body for example, unless of course you adjust "levels" squeezing out all the hightlights.

 

This is FLIR

 

 

 

 

Here you can even identify what vehicles are active, those which were recently used and those parked for an extended time.

 

Edited March 16, 2011 by stormridersp
adding content

[SimFreak]

As a photographer, I can say that for me, this image is not FLIR. Its is a Highly contrasted BW image, more like the result of a Light Intensifier Camera.

 

And more than that. Trees dont have heat of their own like mammals, so they would be at the same temperature as the enviroment that surrounds it. And one last thing. If that wasnt enough, that Hummvee has a very uniform heat signature. In real life, the engine bay would be hotter that its body for example, unless of course you adjust "levels" squeezing out all the hightlights.

 

This is FLIR

 

 

Here you can even identify what vehicles are active, those which were recently used and those parked for an extended time.

 

]

 

FLIR image is highly depended on time of day/night. During thermal-crossover, FLIP becomes useless and EO sensor is your best option. That happens twice in 24hrs. So those images tell us nothing about when that time of thermal-crossover happens. DCS might have simulated image between best time and worst time since it requires so much work to do entire day/night temperature range.

Edited March 16, 2011 by SimFreak

[-NFlight-]

scientifical

 

You just lost the debate.

[Sticky]

You just lost the debate.

 

I am allowed to make mistakes like that, English isnt my first language, I speak five languages, English was the fourth language I learned. Think about that, and ask yourself how well you yourself would do. You didnt know that this is an international forum? :doh:

Edited March 16, 2011 by Sticky

[Moa]

Actually, more advanced physics sees thermal energy in terms of 'statistical mechanics'. An increase in entropy (disorder) in the state of the system (particles) is a result in transfer of energy by photons, and what we notice as macroscopically as 'heat'. The increased disorder may be due to mechanical energy of the system (Brownian motion) or rotational energy around molecular bonds.

 

To understand how temperature affects intensity in the infrared band of the electromagnetic spectrum you can use Planck's Law (if you assume the emitter acts as a 'black body'). Planck's Law gives the spectral radiance at each wavelength for a given temperature.

http://en.wikipedia.org/wiki/Planck%27s_law

Don't look at the equations (you'll go cross-eyed), look at the graphs of the spectral emission for temperature. Notice how hotter objects emit more overall and have distributions with peaks toward lower wavelengths (higher energies). The difference in the wavelengths of the peaks is what IIR (Imaging Infra-Red) cameras use to discriminate objects (of they emit at different temperatures). These cameras must be sensitive to notice the small wavelength changes for different objects (and also need to be cooled so that the camera itself doesn't emit at the wavelengths of interest, or its own emissions would swamp the signals of interest).

 

Objects with similar temperatures to people emit in different parts of the IR band. Cooler objects may emit with peaks at longer (lower energy) wavelengths. On a very hot day trees may have a similar temperature to the temperature of a human body, which makes it hard to distinguish between them in warm weather. In colder conditions (snow on the ground) the difference between ambient and a human is much higher and discrimination is much better.

 

Hot objects (burning vehicles) may emit in the long wavelength end of the visible spectrum. These objects are 'red hot' (visible) with additional emission past red and in the IR part of the spectrum (which we feel as the heat).

 

Even hotter objects (The Sun's photosphere) can emit with a peak at the shorter wavelength end of the visible spectrum, eg. the Sun's peak emission is in the green (which is why plants work at that wavelength and our eyes are especially sensitive to it), although it produces so much light in other colors we see them mixed together as white.

 

That's the emission spectrum. We don't need to worry about the absorption spectrum for objects in the field of view of the Litening pod. They are opaque so you can't see absorption of the spectra of objects in the background. For A-10C we don't worry about this, but in fields such as astronomy they use the fact that some non-emitting (dark) objects such as nebula can be understood by what light they absorb from emitting objects in the background rather than what they emit.

 

I think ED have done a pretty good job of IIR cameras (I have used a real one on a P3 Orion) - especially within the limits of what can be achieved on PC hardware within a reasonable development time.

Edited March 17, 2011 by Moa

[S77th-konkussion]

Yeah-I don't think the DCS Flir is very good at all either. The trees in that shot are all over the thermal map.. I find it quite difficult to find much of anything at ranges usefully better than CCD.

 

However- I hear them saying that there's not much more they can do within the confines of the engine or whatever.. So.. like it or not.. that's what we have for now.

 

Take solace in the knowledge that ED has a history of unexpectedly exceeding expectations more often than not- and their very public standards for DCS don't leave a lot to compromise so... logic dictates that something like this will not be ignored any longer than the limitations require.