Far infrared imagery.

Active imaging experiments are described in the 300 microm-l mm-region of the far infrared (FIR) spectrum. Transmission data are presented for a wide variety of common materials indicating the range of applicability of FIR imaging to law enforcement or nondestructive testing. The FIR images of several objects are presented, and the practicality of FIR imaging is discussed in light of straightforward improvements that can be made in the simple imaging system employed in these studies.