INFRARED CAMERAS
Research Experience for Teachers
Paul Longwell
Summer 2004
What does Infrared mean?
Infrared is the name given to
radiation that has a wavelength
just beyond what our eyes can
detect.
Types of Infrared
Very Near IR
Near IR
Image Courtesy of NASA
Medium IR
Far IR
Very Far IR
Image Courtesy of National Infrared
What is special about an
Infrared Camera?
Image courtesy of FLIR Inc.
Our eyes use visible wavelengths to
create images.
An infrared camera is sensitive to
wavelengths that are longer.
Same Object – Different Images!
Human Eye
Image Courtesy of NASA/IPAC
Infrared
Camera
Infrared Imaging Begins
With Bolometers…
Image Courtesy of PSU/EOC
Think of bolometers as resistors
that are temperature-sensitive.
When an object’s
infrared radiation
strikes a bolometer…
Image Courtesy of PSU/EOC
Enhanced Image Courtesy of PSU/EOC
The resistance of the bolometer
changes, and this is detected by a
electronic circuit.
Bolometer Technology
Gets Moo-ving
In 1901, S.P. Langley
demonstrated that his primitive
bolometer could detect a cow that
was standing out in a field!
Bolometers are not big!
Image Courtesy of PSU/EOC
Each side of a bolometer is usually
0.005 centimeters wide.
A row of 1000 bolometers would
cover a distance of only 5 cm!
Before being used in
cameras, bolometers
must first be tested…
Image Courtesy of PSU/EOC
Sometimes they fail!
Each bolometer helps form
one pixel of an image…
More Pixels = More Bolometers
A typical array of bolometers
contains 240 rows
and 320 columns
Measurements from each bolometer
must be collected separately
Once assembled, the
bolometer array can be
put in a camera.
The lens
focuses
the image
on the
bolometer
An infrared camera
requires an infrared
lens!
Image Courtesy of PSU/EOC
Germanium is used
instead of glass:
Infrared radiation passes
right through, but visible
light does not.
Need a small IR camera?
Image Courtesy of PSU/EOC
This is truly a cool
camera!
Image Courtesy of PSU/EOC
This camera’s detector must be kept
cold with liquid nitrogen!
Cooled Cameras
Image Courtesy of PSU/EOC
•Are more expensive
•Perform better
Images Courtesy of PSU/EOC
Miniature Uncooled
IR Camera
Standard Uncooled
IR Camera
Standard Cooled IR
Camera
MRTD Test
Minimum Resolvable Temperature Difference
Image Courtesy of PSU/EOC
•An image like this is produced by placing a roomtemperature faceplate (w/ slits) over a heated
background.
•The background temperature is brought closer and
closer to the faceplate temperature until the image
cannot be clearly seen.
Applications:
Image Courtesy of PSU/EOC
Examine structures behind walls and floors.
Applications
Light
Switch
Image Courtesy of PSU/EOC
Locate wires behind walls.
Applications
Image Courtesy of National Infrared
Image Courtesy of National Infrared
Image Courtesy of National Infrared
Analyze electrical systems.
Applications
Image Courtesy of National Infrared
Evaluate home heat loss.
Applications
Image Courtesy of National Infrared
Animal Science
Applications
Image Courtesy of Infrared1
Image Courtesy of National Infrared
Image Courtesy of National Infrared
Detect recent activity
Thanks!
• Penn State University – Applied Research
Laboratory (ARL)
• Electro-Optics Center, Kittanning PA
•Ken Freyfogle
•Wendy Gilpin
•Chuck Rapach
Image Courtesy of SE-IR Corp.