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Thermal Imaging using NASA's Infrared Focal Plane Array Technology

I've already introduced the notion of colour temperature and how that relates to seeing using an object's 'heat' as well as its light.

Mark This is Mark McKelvey, who is a member of the Infrared Focal Plane Array Technology Group at NASA's Jet Propulsion Laboratory in Pasadena. The left half of the image is from an ordinary video camera. The right half is a far infrared image (8 to 9 microns wavelength - 'where live bodies glow the best') and actually shows body heat. The forehead is warm and hair is cold. Since the eye is all at the same temperature there is no real detail there.

Back in the mid-1990s, the Infrared Focal Plane Array Technology Group at JPL produced a thermal imaging camera that supercools the sensor and still looks rather like an ordinary camcorder. It uses a technology called a Quantum Well Infrared Photodetector (QWIP for short) and at the time their thermal imaging camera was the world's smallest.

Tom Wynne Transformer

Here are some more QWIP images that Mark sent me. The first is of a colleague of his named Tom Wynne, and you can see the warm blood in the veins in his arm showing lighter than the rest of the arm. Notice how the glasses appear opaque/black because they are opaque at these wavelengths and are cold, not because they are sunglasses. Then there's a colour image of an electrical transformer. Blue is 'cool' and red is 'hot'.

Jet Plume 747 Taking Off in infrared

The two images of aeroplanes were taken at Los Angeles Airport and clearly show the heat of the jet plume from the engines. This is not visible in normal light although you would see the refractive disturbance caused by the strong hot air flow. The other interesting thing is how hot (bright) the tyres are on takeoff.

These images are at about half the resolution of the originals but you can see the level of detail here.

At these wavelengths glass is opaque, thin plastics—such as baloons or bin bags—are transparent and the warmth of a hand lingers as a thermal handprint for a while after the hand is removed. If you thought near-infrared was surreal then the far side is even more so.

More background on infrared photography
Technical background Thermal Imaging IR 'Colour' Mapping
Imaging Abstracts Noctovision  
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My thanks to Mark J McKelvey and California Institute of Technology for NASA Jet Propulsion Laboratory for permission to reproduce their images on this page.