ABSTRACT
A thermograph (TG) is an instrument able to take almost instantaneous infrared pictures of IR-opaque solid or liquid surfaces. When the emissivity of the solid or liquid surface is known, the surface temperature distributions of the observed object, projected onto a plane orthogonal to the TG “optical” axis, can be evaluated. In its most common arrangement the thermograph can be described as a fast-scanning pyrometer that observes finite-dimension surfaces and reconstructs the thermal image on a monitor. High-speed scanning requires a detector with a very short response time. The advantages of photon detectors are that they are more sensitive and have a much shorter response time than thermal detectors. Existing equipment has been evolving and has yielded a large body of experience toward integrated systems with a number of accessories and peripherals. These systems have many similar characteristics but differ in temperature range, sensitivity, frame frequency, and available optics.
