Thermal Imaging

Abstract

Thermography is a generic term for a variety of techniques used to visualize the temperature at the surface of objects and refers to imaging of a full-field temperature distribution. Active heating or passive heating procedures can be used for thermographic imaging of solids (Liezers et al. 1985; Puttick 1987; Vavilov 1992). Thermography provides a map of surface temperature distribution. It can be said that thermography is a noncontact and nondestructive method that gives information about the thermal properties of a sample. The main thermographic methods for solids fall into three major classes: pulse thermography (Lau et al. 1991; Thomas et al. 1995), heating up thermography (Reynolds and Wells 1984), and lock-in thermography (Busse et al. 1992b; Busse 2001). The main differences between the thermographic methods are determined by the type of heating and by evaluation of the thermal properties of the samples. The pulse thermography system records the transient thermal response of an object to a pulse of thermal excitation, provided by a flash tube.