The user of uncooled infrared arrays and systems employing them who is unfamiliar with the technology is confronted with choosing between unfamiliar items. The purpose of this chapter is to assist in making the appropriate choice. The chapter begins with a description of thermal imaging applications. It is followed by a comparison of the principal uncooled thermal detector technologies.
7.2 Thermal Imaging Applications
Table 7-1 illustrates the principal thermal imaging applications as a function of three user communities, namely, military, paramilitary, and commercial. The systems can be either uncooled or cryogenic. The applications fall into four broad categories: surveillance, imaging radiometry, imaging spectroradiometry, and drivers' vision enhancement. Although drivers' vision enhancement can be considered to be a subset of surveillance, its potential market is so large that it can dominate all others; thus it is listed separately.
Surveillance refers to a very broad category of applications in which the user employs a thermal imager to view objects, personnel, buildings, terrain and so on, usually at night but sometimes during daylight. The military distinguishes between surveillance, reconnaissance, and target acquisition, but here these three functions are combined into one. Those military surveillance systems [which are frequently referred to as FLIRs (forward looking infrared)] that are listed in Table 7-1 include weapon sights; examples include those used on an individual weapon such as a rifle, or on a crew-served weapon, such as a two-person missile launcher. They also include the night sight used to acquire and engage targets for the main gun of a tank and the night sight used by a helicopter gunner to acquire and engage targets for missiles carried by the helicopter. Other FLIR examples include the thermal night vision system used by the pilot of a helicopter at night and an emerging technology of finding explosive mines, either lying on the surface of a battlefield or else buried in shallow holes.