Under very specific conditions, the BST image may be better than a microbolometer. The shutter freeze, while a small annoyance, has proven to be of little consequence to firefighters when balanced against the small size and lower cost of most microbolometers. For FDs that want temperature measurement, microbolometers have the advantage of taking the reading from the detector, rather than using a separate pyrometer (which a BST must do). This eliminates aiming issues that occur with BST/pyrometer combinations.Originally Posted by TrojanHorse
In short, while you may like BST imagers (and I do like one feature that used to be exclusive to BSTs, but is no longer), the fire service has overwhelmingly supported microbolometers as equivalent in performance and value. The BST also, contrary to your earlier statement, does not have a higher dynamic range than modern microbolometers. Thus at temperature extremes, the BST will staturate before the microbolometer.
And, just so you don't think I am dodging it, I am still checking on the photon thing. While photons may be applicable for SWIR, I have never heard them used in describing the transfer of heat or LWIR (what the fire service TI usees). I am contacting an engineer at L3/Raytheon for further input. If I am wrong, I'll admit it.
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Thread: The Best Thermal Imager...
10-03-2005, 01:12 PM #41My 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).
10-03-2005, 02:41 PM #42
JB,Would this Photon thing be educated,informed,or smoke? Inquiring minds would like to know,Hehe T.C.
10-03-2005, 05:33 PM #43Originally Posted by Rescue101
Now I am reaching back into my physics days, but the energy of a photon can correspond to a wavelength of light. Certain molecules absorb IR light and will change slightly. Here Trojan Horse is correct. The sensor is probably composed of an IR absorbing material and when it releases the energy absorbed it puts it out as an electrical signal. In most texts I have read the IR spectrum is measured in wavelength, wave numbers and frequency. Photons make the theory a little easier to grasp.
Again this is just from memory.Shawn M. Cecula
IACOJ Division of Fire and EMS
10-04-2005, 09:41 AM #44One guy actually walked into a wall while using it because of the freeze.
Remember, scan - then move, scan - then move."This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?
10-04-2005, 10:25 AM #45
Shawn,Don't try to read so much into the post.Read the "disclaimer" JB puts on the last lines of his posting.I'm just cracking "stones". Yeah Bones,did you catch the phrase '"WALKED" into a wall? You no see your feet,you BETTER NOT BE ON THEM! Camera shutdown is a pretty common happening in our training program. Basics,basics,and more basics.The camera is just a helpful tool.I like testing cameras in the burn house from just smoke to small room fires.I've never needed a camera to find a big fire,although they work well to find sagging floors/ceilings. If you can find Pass alarms in dense cold smoke,you'll probably find anything you want in a heated fire.Scan, move to point,rescan,move.The "freeze"is momentary and obvious,if it happens during your scan wait a nanosecond and rescan.All our students are taught this and are encouraged to swap cameras during training with other "companies"with different brands so they can compare operating charateristics.Plus be familiar should they need to use another brand in a MA situation. Companies found "walking"(yes,we record)are presented obstacles to "persuade"them to change their habits. The cameras we are issued for training are Bullard T3's in various types.They have done a good job surviving the training enviornment and do a good job for what they're asked to do.My personal camera for training is a K-90,I think the picture is a bit better for detail work.But it's also one of the most expensive so not particularly suited for a dept with tight funds.Too many people pick up a camera,use it at training once or twice and think they are camera operators.It takes a LOT of time and experience to be GOOD with a camera. And we're seeing that improper camera use actually puts FF's at RISK. So make sure if you're just getting a camera,get PROPER training to use it.If you already have one make sure the "operators"get annual refreshers.YES,it's that important. T.C.
10-04-2005, 10:47 AM #46Originally Posted by Rescue101
My analytical chemistry experience leads me to believe that the sensor absorbs IR in the 2.5-50 micrometer wavelength range and that the intensity of the IR hitting the sensor would dictate the amount of energy sent to the display. It sometimes helps me to think of an IR source as a lightbulb on a dimmer, increasing the heat output is like turning the dimmer up you get more light. IR is light after all, we just cant feel it.Shawn M. Cecula
IACOJ Division of Fire and EMS
10-04-2005, 10:58 AM #47Originally Posted by Rescue101
Right now, I'm guessing somewhere between "informed" and "smoke."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).
10-04-2005, 10:59 AM #48
Funny you should mention physics.Never cared for physics in school or math either.Now I own a towing business.Care to guess what I have to use everyday? Sometimes ya just gotta think things thru and some days it takes longer than others. Scarcasm? Mwah? Surely you jest,hehe T.C.
10-04-2005, 11:08 AM #49Originally Posted by TrojanHorse
Again, in high heat, the microbolometers generally perform better and give better imagery because of their higher saturation point. In a firehouse (where lots of purchasing decisions are made, even though few TIs are used there), BST can outperform because they can modulate the signal in a stable environment. This "conference room" evaluation process is also why some TI manufacturers tune their software to perform best with the detector at room temperature, rather than significantly elevated (such as you might have after being in a fire environment for 5 or 6 minutes).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).
10-04-2005, 12:40 PM #50
- Join Date
- Mar 2001
My department has 2 MSA's 1 Evolution4000 and a Evolution 5200. The 4000 is a very nice camera but it's big and bulky compare to the very small and light weight 5200. I've used quite a few TIC and the 5200 is on the top of my list.
10-04-2005, 01:37 PM #51Originally Posted by TrojanHorseShawn M. Cecula
IACOJ Division of Fire and EMS
10-04-2005, 02:10 PM #52
How about the Diop Viper (Formerly Cairns Viper). I was very impressed with this camera when I saw it. But then again the guy that demoed it was a factory directy rep kind of guy that knew every thing about the camera.
Another interesting thing was he had a camera that had been loaned out to a VFD that was doing some training. They had one of those little modular hotels that they were training at. 20 or so units all in a line. They were working their way donw the line doing training.
Diop loaned them a viper TIC to evaluate at the training fires. One of the assistant chiefs was in a hotel unit that had been lite. He was playing around with the Viper. His air alarm went off so he decided to leave but he wanted the next crew to use the Viper so he layed it on the table in the room...
Well, they didnt get in their right away and the room flashed over. Got a wee bit hot...the crew asked the *** Chief for the Viper...crap.
Well, it got fried! Realy fried. But when Diop took it back to the lab and cut it open the guts of the TIC still worked! The housing was melted and such the TIC still functioned.
That was impressive. They also have a metal heat sink that can be changed out to help keep them cooler.
Nice TIC, havent seen much about them for a while.
We still ended up going with the MSA back then because of the ergonomics.
I still want to check out the Fire Warrior, have yet to see one in person.-Brotherhood: I don't know half of you half as well as I should like; and I like less than half of you half as well as you deserve.
-Mistakes: It could be that the purpose of you life is to serve as a warning to others.
-Adversity: That which does not kill me postpones the inevitable.
-Despair: Its always darkest before it goes Pitch Black.
10-04-2005, 03:06 PM #53
Originally Posted by firemanjb
- Join Date
- Mar 2003
- New York
We ended up with the 5200 and love every second with it
10-04-2005, 05:16 PM #54Originally Posted by TrojanHorse
Originally Posted by TrojanHorse
10-04-2005, 05:30 PM #55Originally Posted by BaderD
MSA and Indigo chose a 15% pixel saturation point; I believe the earliest 5000s actually had a 25% requirement. There are advantages and disadvantages to setting a high pixel count for saturation prior to triggering the gain change. Most of the other microbolometers on the market have a lower pixel requirement for gain change. In my experience testing engines and software packages, the lower pixel count gives firefighters a better image faster in a hostile environment.
This is just a software change. It can be user set in some circumstances. While 20F is 20F, it is not a big deal in real fires, and the pixel count is artificial, so I still contend there is little change from the 5000 here.
Originally Posted by BaderD
Oh...and those could be the same exact model...just made at different times. The statistics are targets, meaning there is fluctuation based on normal manufacturing tolerances.
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