A:
Short answer –
Thermography is the science of using imaging to measure infrared radiation with
a camera or other device that is sensitive to electromagnetic radiation. The
total range in the electro magnetic spectrum classified as “infrared radiation”
is .8um to 1000um, in thermography we use .9um –14um wavelength range for
imaging.
A:
Long answer – Thermography is a
method used to see and take pictures of the heat an object gives off, or
"radiates". Since every physical object is made up of atoms and molecules that
spin around and vibrate extremely quickly, the temperature of an object depends
on how fast it’s molecules and atoms are spinning. The faster they spin the
warmer the object. For example, a microwave oven makes the molecules of water
in your hamburger spin very rapidly, which causes the food to heat up. Take the
same hamburger and put it into the freezer and it gets colder because the
molecules slow down. Even though you have frozen the hamburger it still contains
heat, to a certain degree. It is still much warmer as compared to, let’s say
dry ice (frozen Co2) at -109 degrees F., and dry ice is a LOT warmer than liquid
Nitrogen which freezes at - 346 degrees F. However NOTHING is colder than an
object at “Absolute Zero” temperature, which is the point at which all the atoms
and molecules slow down to the slowest possible point at which they can be,
“Absolute Zero” which is -459.67 degrees F.
Absolute Zero is the coldest
temperature theoretically possible, so unless you are sitting in a
theoretical freezer reading this, you and all the things around you are
warmer than Absolute Zero and THAT is what makes Thermography such a
valuable tool. It relies on the fact that any object warmer than
Absolute Zero must radiate SOME amount of heat (called Infrared
radiation) and special equipment designed to see this Infrared radiation
can take a picture of it. With that picture, a trained Thermographer
can measure and analyze the heat signature of that object and use the
information to determine several factors about the object and
implications about it's environment.
Here is another way to think
about Thermography: instead of using radiation from the portion of the
electromagnetic spectrum we see in our everyday lives called “visible
light,” we use the longer wavelength radiation from the “Infrared”
portion of the spectrum and take a picture of it called a Thermogram,
hence the term Thermography to describe this science and Thermographer
as the person who practices it.
Why does an Infrared picture have all those funny colors?
A:
Short answer -
A Thermograph or infrared picture is a False Color image which maps the infrared
portion of the electromagnetic spectrum to a specific color in the visible light
portion of the spectrum such that a value of heat is represented by a color we
can see
A:
Within the Electromagnetic Spectrum, there
are lower and higher frequencies of Electromagnetism, but it are all
made up of electromagnetic waves.
At the lower end of the EM spectrum are
waves having a lower frequency and therefore a longer interval or
“Wavelength”, these are your brain waves at about 1-25 hertz, followed
by the 60 cycle power lines or 60 hertz, which is the hum you sometimes
hear coming from electronic equipment. Then radio waves such as AM in
the Kilohertz range and FM in the low megahertz range. Next up in
frequency are Microwaves as in radar transmitters, the “Microwave” oven
in your Kitchen and yes, even that cell phone plastered against your
head several hours a day, Next come, infrared waves which have a
wavelength about the size of a pin head. The infrared camera has a
sensor in it which is sensitive only to this range of electromagnetic
frequency so it can “See” the infrared electromagnetic radiation or what
we commonly call heat.
Next is Visible light, the light we see, the
wavelength of visible light is the size of a Protozoa. The digital
camera has a sensor in it not unlike the one in an infrared camera, but
it sees a
range of electromagnetic frequency which is slightly higher in frequency than
Infrared called, visible light. Interesting fact is, most regular
cameras have a filter built in to keep out Infrared light! We can see
this visible light form of electromagnetic radiation so we think it’s
something special, but it’s not, it made up of the same stuff as
everything else and it only commands a very, very small part of the
total known electromagnetic spectrum.
Well conclude our Electromagnetic discussion
with three more frequencies: Ultraviolet Light with a wave length of
about the size of a Molecule, X-Rays, with a wavelength about the size
of an atom (which is why they can go through your flesh, bones and
teeth) and finally Gama rays and other ethereal cosmic stuff where the
wavelength is about the size of the nucleus of an Atom and smaller
The reason colors in a thermographic or
infrared pictures are funny is because you can’t see Infrared radiation
(or any of the others except for visible light) with your eye so we have
to make up or translate the different frequencies of infrared radiation
into a color you can see. One format for doing this is where the lower
frequencies or frequencies representing less heat are colored Blue to
show the cooler temperatures in the image, Green is not so cool,
Yellow and Orange are warmer colors so they are used to represent warmer
temperatures in the image, Red is hotter and White are the hottest
colors representing the warmest parts of the image. There are many other
types of “Color Pallets” including Black and White where cool is dark
gray and hot is white or light Gray and other various combinations of
colors but they all do the same thing, translate a given frequency
of infrared radiation we cannot see with the naked eye into a visible
color which we can see and which represents a temperature.
As discussed previously every object above the temperature of
absolute zero (minus 459oF) gives off some amount of heat.
Using a specially designed and very sensitive infrared
camera, we can "see" and measure this heat. The camera takes
a picture of the object's surface and shows the temperature
range by displaying it in different colors. The coolest
parts of the object's surface are represented by the cooler
colors of Black, Blue, and Green. The warmest parts of the
image are represented in the warmer colors of Red, Yellow,
and White.
Infrared at work!
We immediately are able to pinpoint the source of the
problem. Cold air (Blue) was leaking in from around the latch and
cooling the surface of the surrounding door frame; this created a cold
draft and was wasting energy. We checked the tradesman's work and found
that during the installation process, he had removed a section of
weather stripping and forgot to replace it.
Because this is a high definition image, there is less guess work and it is easy to
see the fine structures of the door, lockset and its materials. It very
clearly shows the strike plate and latch, and the color coding shows
without a doubt (Blue) where the cold air is entering.
In this next image figure, cold air ( shown in Blue) is
leaking from around the door frame, particularly at the bottom center
area where the doors meet. The air infiltration is creating a draft and
making the entire area in front of the door and the room feel colder.
These owners are wasting
valuable energy dollars as they raise their thermostat to counter the
cold air.
We use the new P640 High Definition camera from FLIR,
the first and largest infrared camera manufacture in the world!
The P640 infrared camera/thermal imager sets a new standard for
professional thermographers with its high-definition 640 X 480 infrared
detector delivering exceptional resolution and image quality for
accurate infrared surveys. As a result, accurate readings can be taken
on smaller objects at further distances. High Definition is what gives
Infrared Imaging Services some of the clearest and most informative
Infrared images available in the industry today with 307,000 individual
temperature measurement pixels, that's 4 times the pixel resolution of
conventional cameras Infrared cameras!
Take a look at the images above, on the
Photos
page and this movie of hot liquid to see how fantastic an infrared image can look when it has
been captured by Infrared Imaging Services using our FLIR P640!
FLIR P640 High Definition
P640 movie of hot liquid in mixing tank.
On Oct. 3, 2008, the President signed into law legislation to
extend many of the Energy Efficiency Tax Incentives first enacted in
2005 but that expired at the end of 2007 or that were scheduled to
expire at the end of 2008. The bill also includes extensions of a
variety of renewable energy tax incentives. This link to the Government
Energy Star web site will provide greater detail:
In Summary for most home improvements like adding insulation,
new energy efficient windows , skylights and doors, new heating and AC
units, you can receive tax credit for 30% of the cost up to $1,500.
Here is the table from the Energy Star website of the types
of credits and what is covered. There are many additional details about
these programs and details may change so please consult the energy star
website before making any purchase decision.
At least half of the energy generated by the “qualifying
property” must come from the sun. Homeowners may only claim
spending on the solar water heating system property, not the
entire water heating system of the household.
The credit
is not available for expenses for swimming pools or hot
tubs.
The water must be used in the dwelling.
The system must be certified by the Solar Rating and
Certification Corporation (SRCC).
Hybrid gasoline-electric, diesel, battery-electric,
alternative fuel, and fuel cell vehicles
Based on a formula determined by vehicle weight,
technology, and fuel economy compared to base year models
There is a 60,000 vehicle limit per manufacturer before
a phase-out period begins. Toyota and Honda have already
been phased out. Credit is still available for Ford, GM and
Nissan.
In the first question, "What is Thermography?" We discussed
that everything above the temperature of Absolute Zero gives off some
amount of heat so if that is true and it is, then the applications for
Infrared analysis are virtually endless!
For example, there are medical uses; if someone twisted an
ankle and it swelled up, Infrared could show how far the inflammation
had spread. It can also look at arthritis, Carpel Tunnel and other
injuries and diseases. Within the electrical industry Infrared is used
to safely detect overloads and loose or corroded electrical distribution
equipment. It is used to detect the signs of roof leaks, tank levels,
clogged pipes and broken valves, building energy loss, electrical motor
inspection, worn out belts and bearings, process equipment such as
heaters and furnaces, air conditioning, steam, printed circuit board
evaluation, pollution tracking, forest fire mapping, surveillance (and
no, it cannot see "through walls" like in the movies) military and
many more applications.
Here is a link to
FLIR corporation's application page. Flir is one of the
industry leaders and a manufacturer of Infrared technology. You will
find they have many very interesting application notes. Because
"everything gives off heat" you may have an idea of how Infrared
technology could work for you, if so, just give us a call, we'd be glad
to discuss your application.
LLC
