LumaSense Technologies BoilerSpection-SD - Manual (Page 43)

BoilerSpection HD/SD Manual Principles of Thermal Imaging 43
6 Principles of Thermal Imaging
All materials above 0 degrees Kelvin (-273 degrees C) emit infrared energy. The infrared energy
emitted from the measured object is converted into an electrical signal by the imaging sensor in the
camera and displayed on a monitor as a color or monochrome thermal image. The basic principle is
explained in the following sections.
6.1 Infrared Radiation
The infrared ray is a form of electromagnetic radiation the same as radio waves, microwaves,
ultraviolet rays, visible light, X-rays, and gamma rays. All these forms, which collectively make up
the electromagnetic spectrum, are similar in that they emit energy in the form of electromagnetic
waves traveling at the speed of light. The major difference between each ‘band’ in the spectrum is
in their wavelength, which correlates to the amount of energy the waves carry. For example, while
gamma rays have wavelengths millions of times smaller than those of visible light, radio waves have
wavelengths that are billions of times longer than those of visible light.
Figure 28: A Spectrum of Electromagnetic Radiation
The wavelength of the infrared radiation ‘band’ is 0.78 to 1000µm (micrometers). This is longer than
the wavelength of visible light yet shorter than radio wavelengths. The wavelengths of infrared
radiation are classified from the near infrared to the far infrared.