If you fly much, you've probably had the experience at one time or another of the pilot announcing a return to the originating airport because of a problem with the plane. This happened to me recently after we all noticed an "electrical smell" and (as I found out later) a couple of circuit breakers had tripped. So we landed back where we started fully expecting to be immediately taken off the plane. Instead, chased by fire trucks with sirens blaring and lights flashing, the aircraft was taken directly to a remote section of the airport to be immediately boarded by several firefighters armed with infrared-based imaging equipment—they were searching for hotspots hidden within the fabric of the plane. A disconcerting experience to be sure, but it emphasizes the growing importance of imaging technologies in our everyday lives. Investigative imaging in particular has taken on new significance in the aftermath of September 11, 2001, and the continuing threat to homeland security. Our special supplement on investigative imaging, which follows p. 68, describes several technologies that can image through opaque materials to help detect not only hidden weapons but microscopic particles as well.
While on the subject of things hidden, I wonder how many of us know what's really under the hood of our cars? The engine of course . . . but what was once an almost entirely mechanical system has become merely the nucleus of an increasing plethora of electronic and optoelectronic devices that control everything from engine emissions to the (automatic) windshield wipers. Until recently these parts all communicated over copper cables routed throughout the car; but optical fiber is starting to push the copper aside and can be found under the hood of several of today's high-end vehicles (see p. 51). Another technology making headway in the transportation arena is solid-state lighting. Many cars now are produced with light-emitting diodes (LEDs) in place of certain incandescent bulbs, and new traffic lights also use LEDs. In fact the entire market for advanced lighting technology is currently very active and attracting much attention (see p. 13).
As for the plane ride . . . the IR imagers enabled the firefighters to release the aircraft, confident that there was no hidden fire, for which we passengers were thankful . . . but we wondered why we were made to stay on the plane while it was considered too unsafe to move near a terminal.