Infrared Techniques for Surveillance and Crime Deterrence

There are millions of dollars worth of optical surveillance equipment in use, nearly all of it useless after dark. To provide greater security in the dusk to dawn period, a number of infrared surveillance devices have been developed. A variety of techniques are now being employed, including pulsed and continuous-wave beams in both the direct and backscatter detection modes. The unique advantages of infrared technology relative to ultrasonics and microwaves will determine future trends in the area of surveillance and crime deterrence.