Infrared vision: visual inspection beyond the visible spectrum

Infrared (IR) vision for the nondestructive testing (NDT) of materials has considerably grown in the last few years as a results of the continual technological progress and the development of advanced signal processing techniques. Typical applications can be divided into two groups: (1) reflectography/transmittography in the near (NIR) and short-wave (SWIR) infrared spectra, which have been recently applied in the inspection of semitransparent composite materials such as glass, aramid–phenolic, and a variety of natural fibers; and (2) infrared thermography, which involves the detection of surface and subsurface defects based on the differences in thermal signatures in the mid-wave (MWIR) and long-wave (LWIR) infrared bands. Infrared reflectography and thermography have shown interesting complementarities between them as well as with other NDT methods such as ultrasound testing, eddy current testing, and holographic interferometry. In this chapter, a review of classical and recent applications of infrared vision is provided and discussed in detail with examples.