Gain level - Current fire service TIs have automatic gain adjustment systems, so firefighters do not have to be concerned with adjustments. The gain adjusts based on the amount of thermal energy in any scene. Microbolometers commonly have two gain levels - "normal," or high gain, and "EI mode," or low gain. When these TIs switch modes, the shutter will fire and there will be a momentary freeze of the image.
THERMAL IMAGING TRAINING >>> By BRAD HARVEY Thermal Imaging Terminology What Does All the Technical Stuff Really Mean? T he Fire Department Instruc- cessing hardware and software play a amount of energy that it can receive and tors Conference (FDIC) is one greater role in determining picture qual- process. If the sensor is exposed to more of my favorite activities of the ity. The detectors in the fire service are heat (thermal energy) than it can mea- year, as I get an opportunity to interact available as 80x60, 120x120, 160x120 or sure, then it has reached its saturation with firefighters from all over the world 320x240 pixels. Most TIs use a 160x120 point. Therefore, if a sensor can receive who come by the booth to talk about detector. The 320x240 up to 1,000 degrees Fahren- thermal imaging. The show allows me to ask questions, answer questions and detectors have four times more pixels than A thermal heit in energy, then it cannot detect or display a difference really get a feel for what is on the minds of firefighters when it comes to thermal the smaller detectors. Generally speaking, the imager is between a 1,000ºF item and a 1,500ºF item – the most imaging. On the drive home, I was re- flecting on the questions and interac- higher the resolution will yield a better po- a highly it can sense is 1,000ºF. If a large number of pixels be- tions over the previous five days and felt like I had spent quite a lot of time at the tential for image qual- technical piece ity. Price will rise or fall come saturated, then an im- age may be mostly white or show explaining technical terminology to firefighters. Some were confused by with resolution more than with any other fea- of equipment, clouded by white. This is not “white out.” The detector, sales pitches that they had heard and others were confused by sales literature ture of a thermal imager. The key is to determine but you don’t and thus the TI, is perform- ing properly. It has been ex- they had read. While a thermal imager (TI) is still a highly technical piece of what resolution is suffi- cient for your needs and have to be an posed to a significant heat source and is generating a equipment (resulting in the need for technical literature and sales presenta- budget. • White out – This engineer to mostly white image as a re- sult. This should be a danger tions), you do not need to be an engi- neer to understand the terminology. term is a holdover from the early days of fire ser-
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