Infrared Imaging is also referred to as the art and science of
thermography. I say art and science because the science aspect is the imaging
device’s ability to “see” heat energy in the infrared wavelength
range which is normally invisible to the naked eye. The art aspect is the certified
and experienced thermographers’ knowledge of heat transfer principles, proper
adjustments of the imaging device and the interpretation of the thermal images obtained.
By now most people have had some exposure to thermography
through the various media sources. It is technology that was originally developed
for military applications in order to see hot objects, i.e. operating trucks and
equipment, personnel, etc. when under the cover of darkness or camouflaged. As
this new technology was declassified, it began to find its way into various
industries, initially the computer chip manufacturing process where it is used
to find electrical faults and short circuits on a microscopic scale before chips
are installed. Now it seems that new applications and uses for thermography are
emerging at a rapid pace.
Think of it in these terms, anytime knowledge regarding the
temperature of an object relative to a given standard or in comparison with another
similar object would be beneficial, thermography is a very useful non-destructive tool.
Manufacturing companies are using it to keep their process
equipment operational and to limit or eliminate down time. Insurance companies
are requesting that thermography be used to inspect the electrical distribution
systems in commercial facilities for fire and life safety and prevention of
down time losses. Municipal electric utilities are using it to keep the power
grid safe and operational. These are just a few examples.
So how does infrared imaging work? The imaging device has
an electronic detector behind the lens which collects data from the infrared
wavelength range within the field of view and converts this data to a visible
light spectrum (typically white and red colors represent hotter areas and blue
and violet colors represent cooler areas). Think of the device as mapping out
“heat contours” across the surface of the object similar to an
elevation contour map of a geographic area indicating mountains and valleys.
Who can do infrared imaging? Only trained, certified
and experienced individuals should attempt thermography. There are currently three
levels of certification being taught by a few organizations meeting the various
governmental training standards. Level I is the lowest certification and Level
III is the highest certification. Certified thermographers are well trained in
the physics of heat transfer through various materials and the ability to make
adjustments on the imaging device to obtain accurate temperature data. Accurate
is the key work in the last statement. For comparison, almost anyone can pick
up even the most sophisticated visible light camera and probably take a picture,
but will it be in focus? Will the aperture be set properly to allow the right
amount of light in? Will the proper lens or filter be selected? Just as taking
pictures with a sophisticated visible light camera is hardly “point and
shoot”, neither is thermography. The variables and the possibility for
errors are practically endless.
I could go on and on about this topic and include more information
than you probably want to digest, but this covers the basics and you should now have
a passing knowledge of how the technology works. Please visit the other pages in this
site for more in-depth information regarding the various applications of thermography.
