ABSTRACT
Infrared refers broadly to that portion of the electromagnetic spectrum starting at the deep red (the point at which light just begins to become visible, hence the name infrared) and extending to the microwave radar region. As shown in Figure 1, the relative position of infrared region of the electromagnetic spectrum is in the wavelength range of 0.75 to 1000 µm. Infrared waves are described as short, medium, or long wave. Short infrared waves (or near infrared) are closest to visible light. Because much of this energy is light, it is easily reflected. Short infrared waves occupy the region of the electromagnetic spectrum in the wavelength between 0.75 and 3.0 µm. The long infrared (or far infrared) waves, spanning the wavelength region of 25-1000 µm, are readily absorbed by most materials as heat. The medium waves (or middle infrared) occupy the region between the short infrared and long infrared regions [1].
