LWIR Camera

See how objects of different temperature emit different intensities of infra-red radiation.

LWIR camera LWIR camera

What It Shows

The Long Wave Infra-Red (LWIR) camera is sensitive to wavelengths in the 7µm-14µm range. The output of the camera is NTSC video through a BNC connector. The image data is monochrome, with no direct spectral information.

Some objects that are opaque in the visible spectrum can be transparent to IR—this can be shown by placing a green trash bag over a volunteer. Materials such as plexiglass, on the other hand, give equally surprising results.

LWIR camera LWIR camera

How It Works

Power is provided by a 6V lead-acid gel cell battery with special DC pin-to-alligator clip cable. The camera takes about 30-60 seconds to "warm up"—ironically by cooling down the infra-red sensitive microbolometer array (320x240 pixels). Uncooled, this array would drown in its own thermal noise. As the sensor cools down, noise resolves into an image.

The camera lens has the usual focus and iris rings, which will need to be adjusted by the user for best results. The lens is visually opaque germanium.

Setting It Up

For secure handling the camera is on a lecture bench or cart, and shimmed to raise the lens. The camera assembly sits atop a box of video electronics. On the front of the camera is a Color button that cycles through four color schemes for the video: B/W with white==hot, B/W with black==hot, and two color mappings of the same intensity data that accentuate different intensity ranges.

Comments

There is an auto-brightness function that causes a cool aura around hot objects, and a warm one around cold objects—this is an artifact. Although the camera is excellent at showing temperature differences qualitatively, it is not practical for obtaining accurate temperature values. Zoom is useless, as is Freeze.