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 Medium IR Far IR Very Far IR Image Courtesy of NASA Image Courtesy of National Infrared

What is special about an Infrared Camera? Our eyes use visible wavelengths to create images. An infrared camera is sensitive to wavelengths that are longer. Image courtesy of FLIR Inc.

Same Object – Different Images! Infrared Camera Human Eye Image Courtesy of NASA/IPAC

Infrared Imaging Begins With Bolometers… Think of bolometers as resistors that are temperature-sensitive. Image Courtesy of PSU/EOC

When an object’s infrared radiation strikes a bolometer… The resistance of the bolometer changes, and this is detected by a electronic circuit. Image Courtesy of PSU/EOCEnhanced Image Courtesy of PSU/EOC

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! Each side of a bolometer is usually centimeters wide. A row of 1000 bolometers would cover a distance of only 5 cm! Image Courtesy of PSU/EOC

Before being used in cameras, bolometers must first be tested… Sometimes they fail! Image Courtesy of PSU/EOC

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! Germanium is used instead of glass: Infrared radiation passes right through, but visible light does not. Image Courtesy of PSU/EOC

Need a small IR camera? Image Courtesy of PSU/EOC

This is truly a cool camera! This camera’s detector must be kept cold with liquid nitrogen! Image Courtesy of PSU/EOC

Cooled Cameras Are more expensive Perform better Image Courtesy of PSU/EOC

Miniature Uncooled IR Camera Standard Uncooled IR Camera Standard Cooled IR Camera Images Courtesy of PSU/EOC

MRTD Test Minimum Resolvable Temperature Difference An image like this is produced by placing a room- temperature 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. Image Courtesy of PSU/EOC

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 Analyze electrical systems. Image Courtesy of National Infrared

Applications Evaluate home heat loss. Image Courtesy of National Infrared

Applications Animal Science Image Courtesy of National Infrared

Applications Detect recent activity Image Courtesy of National Infrared Image Courtesy of Infrared1

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.