Understanding Infrared Thermography Reading 3

108. Spatial resolution - The spot size in terms of working distance. In an infrared
radiation thermometer this is expressed in milliradians or as a ratio (DId) of the
target spot size (containing 95 percent of the radiant energy, according to
common usage) to the working distance. In scanners and imagers it is most often
expressed in milliradians.
109. Spectral response - The spectral wavelength interval over which an instrument or
sensor responds to infrared radiant energy, expressed in micrometers (}lm) - also,
the relative manner (spectral response eUlVe) in which it responds over that
intelVal.
110. Specular (('Occtor - A smooth refl ecting surface that reflects all incident radiant
energy at an angle complementary (equal around the nomlal) to the angle of
incidence, A mirror is a specular refl ector.
111. Spot - The instantaneous size (diameter unless otherwise specified) of the area
at the target plane that is being measured by the instrument. In infrared
thermometry, this is specifi ed by most manufacturers to contain 95 percent of
the radiant energy of an infin itely large target of the same temperature and
emissivity.
112. Storage operating range - 1be temperature extremes over which an instrument
can be stored and. subsequently, operate within published performance
specifications.
Charlie Chong/ Fion Zhang