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How does an infrared thermometer work?
Each object transmits infrared rays. The power of these rays depends on the type
of material (expressed as “radiation coefficient” or “emissivity” of a material) and of
course the temperature of the object. An infrared detector absorbs these rays and the
electrons in the device turn them into temperature (° C or ° F).
This thermal camera shows the temperature of all objects in the vicinity on a thermal
image (color scale with, for example, blue is cold and red is warm). This camera can
mix the thermal image with an optical image. This will make the measuring area more
visible and you can understand where a cold or hot spot is exactly.
Radiation coefficient or emissivity
The amount of infrared energy radiated by an object is proportional to the tempera-
ture of the object and the ability of the material to radiate energy. This ability refers
to “radiation coefficient” or “emissivity”. Emissivity is the ratio of the average emission
power to a black radiator at the same temperature. Emission is for most materials
between 0.10 and 1.00. Materials with low emissivity (<0.60) emit little energy, typi-
cally for materials with a shiny, light surface (eg metals). Materials with high emissivity
(>0.90) emit much energy, typically for matte dark areas. The lower the emissivity, the
more difficult it is to accurately measure.
The emissivity values of Temppointer 1 are set at 0.95.
Less accurate measurements will be made for measurements on shiny, highly reflec-
tive or polished surfaces. To compensate, cover the surface with a masking tape or a
flat black paint. Give the tape time to assume the surface temperature. Then measure
the temperature of the tape or the painted surface.
