National Aeronautics and Space Administration

Glenn Research Center

Isaiah Blankson

“Passive Millimeter Wave Imaging for Aviation Safety and Homeland Security”

This talk discussed the applications and capabilities of passive millimeter wave imaging. This is a sensing technology that detects electromagnetic radiation with wavelengths on the millimeter scale (approximately 3-10mm). All objects emit electromagnetic radiation. The unique quality about millimeter waves is that their wavelength is long enough to allow the radiation to pass though obstacles such as dust, smoke, fog, and even clothing that hinder other sensing devices such as infrared and optical sensors. Furthermore the sensor functions passively, by receiving the radiation that is naturally emitted by objects. Thus, one can observe objects, individuals or environments without being detected (you can observe someone without them knowing that you are watching them).

The unfortunate weakness of millimeter wave imaging is that it does not produce very high resolution images (images are often blurring and noisy). The resolution scales with the size of the aperture of the sensor. Thus the aperture must be quite large to obtain superior resolution. However, when images provided by millimeter wave imaging are merged with those from optical sensors, a significantly clearer picture is yielded.

This technology has a wide range of applications. It can aid in medical diagnosis of tumors and assist in maintenance. One particularly interesting application is homeland defense, since this sensor can peer through clothing revealing hidden weapons and contraband. This technology has enormous potential, however much research still remains to be conducted in the areas of image recovery, radiometer design, super resolution mathematic algorithms, etc.

Passive millimeter wave imaging sensors can provide visual-like images through atmospheric and environmental conditions that would render infrared and visual sensors useless.