Thread: TIC and Glass

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    Default TIC and Glass

    Anyone know why you cant see through glass with a TIC?
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    Glass reflects and blocks the IR spectrum I believe.
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    Glass reflects and blocks the IR spectrum I believe.
    Sounds about right. Also polished metals like brass, aluminium, etc., will also reflect the IR spectrum.

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    I believe a pool of water does, also.........

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    You see the heat of the glass not the image on the other side. In the IR world glass is no different than concrete. Same with water etc.

    If your board one night and have a stainless steel pump panel stand infront of it looking at it with a TIC-----might see a ghost!
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    This explanation could be very technical but I will keep it simple because all of that technical stuff is not going to do you any good on the street at 3:00 in the morning.

    Fire Service TICs (Thermal Imaging Cameras) work by detecting LWIR (Long Wave Infrared) that has a wavelength of 8-14 Microns.

    Based on this wavelength, LWIR is capable of cleanly passing through some things and it will be absorbed or reflected by others.

    LWIR CAN cleanly pass through:
    air, smoke, fog

    LWIR can NOT cleanly pass through:
    water, ice, glass, plastics, metals, and any most "solid materials"

    I am going to post some pictures with additional info to demonstrate some examples.

    I can't tell you the number of times I have seen firefighters misusing a TIC because they do not truly understand how they operate. Trying to use them to see through glass and water to locate victims is classic example.

    For additional information on TICs here are some other recent discussions and websites that will help:

    http://cms.firehouse.com/forums2/sho...threadid=56676

    http://cms.firehouse.com/forums2/sho...threadid=55266

    http://cms.firehouse.com/forums2/sho...5&pagenumber=1

    www.safe-ir.com

    http://thermalimager.bullard.com/index06.cfm

    backdraft663, thanks for your question, I am sure there are many others out there who had the same question and will learn from the response.

    If anyone has an experience with a TIC, good or bad, that everyone can learn from PLEASE share it.

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    Good Luck, Stay Safe,
    Mike Richardson
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    "aka TIman"
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    The information and views above are in no way associated with my employer, and are strictly my own.

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    Here is an example of how TIC works with water.

    The visible light your eye uses will pass through the water to a certain extent so you can "see through" water with your eyes.

    The LWIR the TIC uses will be absorbed or reflected by the water so the TIC can not "see through" water.
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    Mike Richardson
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    St Matthews FD, Louisville KY
    "aka TIman"
    richardson@stmatthewsfd.com

    TI Training = www.safe-ir.com

    The information and views above are in no way associated with my employer, and are strictly my own.

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    Here is an example of how you can get a reflection or "Ghost" as stm4710 put it.

    The LWIR is being reflected off of the side wall which is covered with a reflective aluminized insulating material.

    This could be a very common scenario inside of a commercial building. Better hope you can figure out which door is really there!

    If you are not sure if you are looking at a relfection with a TIC:

    Wave, if the Firefighter waves back chances are it is a reflection.

    Change your viewing angle, the reflection may go away or you may be able to pick up on it being a reflection.

    Physically check it out, when all else fails you may have to physically check it out.
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    Mike Richardson
    Captain, Training Officer
    St Matthews FD, Louisville KY
    "aka TIman"
    richardson@stmatthewsfd.com

    TI Training = www.safe-ir.com

    The information and views above are in no way associated with my employer, and are strictly my own.

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    Here is an example of plastics.

    This is an example of a "plastic" door that you may encounter in a commercial building.

    Once again, the visible light your eyes use will "pass right through it".

    However, the LWIR the TIC is trying to use is being absorbed or reflected.

    *Exception to the Rule*
    LWIR can pass through some thin plastics. If you put a trash bag over your TIC, it will "see through it"
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    Mike Richardson
    Captain, Training Officer
    St Matthews FD, Louisville KY
    "aka TIman"
    richardson@stmatthewsfd.com

    TI Training = www.safe-ir.com

    The information and views above are in no way associated with my employer, and are strictly my own.

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    Our new K90 TIC has an Overlay feature that is supposed to help with looking through glass. I personally havn't tried playing with it looking through glass so I can't comment on its effectivness. I persnally think its just another button to confuse people.

    I would rather the camera have just one on/off button and thats it.
    Last edited by ffemtreed; 01-30-2004 at 02:32 PM.

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    Excellent pictures Capt. Richardson. They really show what you are talking about.
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    The heat is reflected back from the window. You can not see through the window (flames) but you can see what is also termed as a "halo" around the window.
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    Originally posted by ffemtreed
    Our new K90 TIC has an Overlay feature that is supposed to help...
    The "overlay" in ISG cameras is simply a visible light camera which is mixed with the signal from the TI sensor. While it will "see" through glass and it will also add some texture to your TI vision, it only works when you would be able to see anyway, smoke will obscure it resulting in a TI image only.

    Basically, if the overlay feature is working you don't really need the TI unless you are looking for hotspots. If you're in a place where you need the TI the overlay will not help you until visibility improves.
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    what great photos .........and good information !! thanks Capt !
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    Here is some more info/examples on glass & TICs.

    Remember, when it comes to glass basically 1 of 4 scenarios will come into play.

    Scenario #1 - You can have objects and/or victims behind the glass in which case you will not see them with the TIC. However you may ďseeĒ reflections from the same side you are viewing from. There is one exception to that rule which involves old single pane glass, see Scenario #2 more info on that exception. (Photos for Scenario #1 Below)
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    Mike Richardson
    Captain, Training Officer
    St Matthews FD, Louisville KY
    "aka TIman"
    richardson@stmatthewsfd.com

    TI Training = www.safe-ir.com

    The information and views above are in no way associated with my employer, and are strictly my own.

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    Scenario #1 - Can't see anything on the other side, getting a reflection from the side you are looking from.
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    Mike Richardson
    Captain, Training Officer
    St Matthews FD, Louisville KY
    "aka TIman"
    richardson@stmatthewsfd.com

    TI Training = www.safe-ir.com

    The information and views above are in no way associated with my employer, and are strictly my own.

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    Scenario #2 Ė You have an old single pane glass window, due to its construction LWIR can pass through it. In the photo below you can actually see flames from a fire through an old single pane window. This obviously can be confusing if you are not sure what you are looking at.
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    Mike Richardson
    Captain, Training Officer
    St Matthews FD, Louisville KY
    "aka TIman"
    richardson@stmatthewsfd.com

    TI Training = www.safe-ir.com

    The information and views above are in no way associated with my employer, and are strictly my own.

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    Scenario #3 Ė You can have a victim or object that is in direct contact with the glass, which will produce a "heat signature" on the outside glass surface due to heat or energy being physically conducted through the glass. This will produce some form of heat signature that may or may not be recognizable. Example: a victim is leaning against a window or glass shower door, after 2-5 minutes heat will pass through the glass to produce ďan imageĒ when viewed with the TIC on the other side.

    Sorry don't have a photo handy for this one but I will get one and post it. I am sure you can get an idea of what it would look like from the description.
    Mike Richardson
    Captain, Training Officer
    St Matthews FD, Louisville KY
    "aka TIman"
    richardson@stmatthewsfd.com

    TI Training = www.safe-ir.com

    The information and views above are in no way associated with my employer, and are strictly my own.

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    Scenario #4 Ė You have a fire that is heating up the inside of a house or room. The fire will heat the glass/windows, the windows will get hotter which you should be able to detect with TIC. Remember you will not see the flames or fire directly but the heat that is being transferred to/through the windows. Also remember newer energy efficient double & triple pane windows will retain more of the heat and may actually hide a substantial heat condition.

    Top Photo - Heavy heat condition behind both windows. Working Fire!

    Bottom Photo - Minor? heat condition behind middle window. Not Sure!
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    Mike Richardson
    Captain, Training Officer
    St Matthews FD, Louisville KY
    "aka TIman"
    richardson@stmatthewsfd.com

    TI Training = www.safe-ir.com

    The information and views above are in no way associated with my employer, and are strictly my own.

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    Default Re: TIC and Glass

    Originally posted by backdraft663
    Anyone know why you cant see through glass with a TIC?
    Just like light doesn't go through most materials, neither does infrared. Remember that in general, your TI wants to see surface temperatures. Glass has a surface, and therefore, the TI tries to create an image of it. It also happens that glass is reflective of heat as well, and therefore can show nearby heat images.

    The ability of different energies to penetrate different materials is based partially on wavelength. Just think about how AM and FM radio signals act differently, or how your FD radios work great in some situations and terribly in others. The IR wavelength that your TI uses penetrates just a few solid materials. In reality, that is not much different than your eyes...they only see through a few solid materials as well.

    It's just that the solid materials are different for TIs and human eyes. The best way to adjust to this difference is to regularly use and train with your imager.
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    Originally posted by ffemtreed
    Our new K90 TIC has an Overlay feature that is supposed to help with looking through glass. I personally havn't tried playing with it looking through glass so I can't comment on its effectivness. I persnally think its just another button to confuse people.

    I would rather the camera have just one on/off button and thats it.
    Because the video overlay mixes a percentage of video camera with a percentage of thermal image, it can cause problems in dark environments. Say the overlay uses 40% video and 60% thermal. If you try to look through a window into a dark room with overlay, you will see 40% darkness (a video camera sees what your eyes see, although usually not as well) mixed with 60% reflection off the glass (combined with the actual temperature of the glass). In short, you will not see anything in that room.
    My comments are sometimes educated, sometimes informed and sometimes just blowing smoke...but they are always mine and mine alone and do not reflect upon anyone else (especially my employer).

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    firemanjb's observations are technically accurate as stated, but the TICs on the market that have video overlay use a scheme that is closer to 70% video / 30% thermal.

    The object of the video overlay is to allow the fire fighter to stay focused on the specific hot spot or heat source and see the visible spectrum as well. It helps immeasurably in identification of potential hazards and still-burning embers. This feature allows for better, faster decision-making on the fire ground.

    You can talk to user's of the ISG K-90 with video overlay and find out what they are using it for. Safe-IR is always a good source for tactical information and, of course, for good, solid TIC training.

    We have some streaming video on our web site that illustrates the video overlay option. www.isgfire.com

    David Fisher
    Business Development Manager
    ISG Thermal Systems USA, Inc.

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    Originally posted by davidf
    firemanjb's observations are technically accurate as stated, but the TICs on the market that have video overlay use a scheme that is closer to 70% video / 30% thermal.

    The object of the video overlay is to allow the fire fighter to stay focused on the specific hot spot or heat source and see the visible spectrum as well. It helps immeasurably in identification of potential hazards and still-burning embers. This feature allows for better, faster decision-making on the fire ground.
    David: I thought your primary overlay competitor used a 30% video; I don't know your specific % for video. 70% strikes me as high, though, from when I have used it.

    But, I do want to call you on your statement that the user can focus on "hazards or still burning embers." If the ember is burning, my THERMAL should show it...and if the smoke is too dense for my eyes to see it, chances are the video overlay won't either. If the smoke isn't dense, if I mererly look at the wall, the orange glow could indicate where the embers are, right?

    There may be applications for video overlay, but dark or smokey conditions (where the thermal imager excels) are probably not the right ones since the absence of visible light makes the video camera perform poorly.

    Jonathan Bastian
    My comments are sometimes educated, sometimes informed and sometimes just blowing smoke...but they are always mine and mine alone and do not reflect upon anyone else (especially my employer).

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    Jonathon:

    The Video Overlay installed in ISG K90 Talisman cameras do not see through smoke. We know that. But, as my associate Dave Fisher indicates, the application for the Overlay is not to see through smoke Ė that is what the infrared detector part of the Talisman does.

    I think youíre assuming that you only use thermal cameras in zero visibility (smoke) conditions Ė basically in internal attack applications. But most manufacturers know that thermal imagers are used over 90 percent of the time in non-smoke environments. Most of the time, cameras are used in nuisance calls, smell of smoke, overhaul, size-ups, routine stuff. There are a million ways you could use a thermal camera outside the involved structure.

    The lens on a firefighting thermal imager is typically 50 degrees FOV (this includes your cameras [Bullard models]). The imaging capability is never one-to-one. Instead, images appear smaller in the camera than if you were looking at them with the naked eye. Because of this effect the overlay can be used in virtually every situation where environment is better than zero visibility to help give the firefighter guidance and depth perception.

    For instance, letís assume I was in a warehouse, called-in because of the smell of smoke. Iíd probably want to use the thermal camera to find an overly hot ballast. Problem is, the ceilings in warehouses are typically very high, and ballasts are many times pretty close together.

    With overlay I can see the hot ballast and identify exactly which one is hot much more accurately and definitively from afar because I can reference everything around it. My depth perception is very much improved, my ability to resolve low contrast objects is also very much improved. Think of it as using a camcorder with camcorder image quality, superimposed with the heat signature of hot objects. You canít get that from a straight thermal camera.

    Now, if I were in an attack situation, in zero-visibility, Iíd simply not use the overlay Ė in that scenario overlay is pretty much useless Ė but remember it was not designed to be used in fire attack situations. That is when Iíd use a straight thermal imager.

    Video cameras donít see through smoke. Plain and simple. I think we all know that. But itís added versatility to have both a video camera and thermal imager in one.

    The vast majority of ISG K90 Talisman cameras are sold with the video overlay option installed. For what little extra it costs the department, firefighters feel itís worth it.

    You referenced the mix on IR/Visual for our one major competitor with video overlay. You are referring to ISI I assume.

    I have no idea what their visual/IR mix is. We havenít really paid a lot of attention to that. I guess itís because we donít see them that often and assume there arenít that many people buying that brand.

    The latest surveys suggest that almost nine out of every ten departments worldwide who buy cameras buy from one of the three leading brands Ė Bullard, MSA or ISG.

    Thermal imagers are kinda like SCBA now. (The vast majority of departments choose Scott or MSA airpacks. Few have others like Draeger, Interspiro or whatever.)

    Thanks Jonathon, take care, Iíll see you at FDIC.

    David A. Little
    Chief Executive Officer
    The ISG Group

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    Thanks for the posts Dave, you know I always liked the ISG and using the overlay certianly improved the depth perception while training, I never really thought of it as a useful tool until you "enlightened" us!

    My current FD uses Bullards (against my recomendation ISG was never considered for lack of a pocket TIC which you have since corrected) and there are definitly times when I'm looking through the camera then with my eyes and back to camera trying to figure out what that hot spot is that I'm looking at (most recently a Sig pistol in a car fire ) and I now realize the potential of the overlay.

    Thanks again, maybe next time I'll convince the powers that be to give it a whirl.
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