We see temperature and temperature differences!!!
48
CG320 & CG640 Manual
12. Reference: Emissivity
12.1 Radiation measurement
Any object that has an absolute temperature greater than 0 degrees Kelvin (0K or -
273.15 ° C or
-
459.67 °
F) emits infrared radiation.
Ice-cold objects also emit infrared radiation if the temperature is above -
273 ° C. The hotter the object, the
more heat it emits.
The larger the temperature difference between the objects and its surroundings, the clearer the thermal
image.
However, the contrast of the thermal image depends not only on the temperature but also on the emissivity
of the objects.
12.2 Emissivity and Reflection
All materials have an emissivity (e) of 0 to 1.
The so-
called "black body" absorbs all incoming radiation, so ε = 1.
On the other hand, high reflectance materials have lower e.
Most materials such as wood, concrete, stone, human skin and vegetation have a high emissivity in the
LWIR area (0.9 or higher).
However, most metals have a low emissivity (less than 0.6) with surface finish.
The higher the glare on the surface, the lower the emissivity.
Heat that is not absorbed by the material is reflected.
The higher the reflected energy, the greater the risk of misinterpreting the measurement results.
To avoid this misinterpretation, it is important to adjust the camera's angle of view to minimize reflections.
In general, if a substance acts like a mirror in a visual spectrum, it can also act as a mirror in the LWIR
region.
Such materials may be difficult to monitor because the temperature is sensitive to other objects reflected
in the monitored object.
In general, thermal imaging cameras in COX work best on objects with high emissions (over 0.9), and
temperature measurements on objects with low emissions (below 0.6) can be inaccurate.
12.3 Accuracy in measurement
The accuracy of the measurement using thermal imaging camera depends on the surrounding situation.
In order to obtain maximum performance from such a camera, the measurement conditions must be
