Page 194 - Intro Predictive Maintenance

Thermography 185

Emittance Power radiated per unit area of a radiating
surface.
Far-infrared Infrared radiation extending approximately
from 15 to 100 micrometers.
Gamma ray A high-energy photon, especially as emitted
by a nucleus in a transition between two
energy levels.
Hot spot An area of a negative or print revealing
excessive light on that part of the subject.
Infrared band The band of electromagnetic wavelengths
lying between the extreme of the visible
(approximately 0.70 micrometer) and the
shortest microwaves (approximately 100
micrometers).
Infrared radiation Electromagnetic radiation lying in the
wavelength interval from 0.7 to 1,000
microns (or roughly between 1 micron and
1 millimeter wavelength). Its lower limit is
bounded by visible radiation, and its upper
limit by microwave radiation.
Isothermal mapping Mapping of all regions with the same
temperature.

Microwave band The portion of the electromagnetic spec-
trum lying between the far-infrared and the
conventional radio frequency portion.
Although not bounded by definition, it is
commonly regarded as extending from 0.1
cm (100 microns) to 30cm in wavelength (1
to 100 gigaHertz frequency).
Mid-infrared Infrared radiation extending approximately
from 1.3 to 3.0 micrometers and being part
of the reflective infrared. Often referred to
as short-wavelength infrared radiation
(SWIR).
Near-infrared Infrared radiation extending approximately
from 0.7 to 1.3 micrometers and being part
of the radiative infrared.
Qualitative infrared thermography The practice of gathering information about
a system or process by observing images of
infrared radiation and recording and pre-
senting that information.