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Basics of Infrared Thermometry
thermoMETER CT
13.
Basics of Infrared Thermometry
Depending on the temperature each object emits a certain amount of infrared radiation. A change in the
temperature of the object is accompanied by a change in the intensity of the radiation. For the measurement
of “thermal radiation” infrared thermometry uses a wave-length ranging between 1 μ and 20 μm. The intensity
of the emitted radiation depends on the material. This material contingent constant is described with the help
of the emissivity (
e
- Epsilon) which is a known value for most materials
Infrared thermometers are optoelectronic sensors. They calculate the surface temperature on the basis of the
emitted infrared radiation from an object. The most important feature of infrared thermometers is that they en-
able the user to measure objects contactless. Consequently, these products help to measure the temperature
of inaccessible or moving objects without difficulties. Infrared thermometers basically consist of the following
components:
- Lens
- Spectral filter
- Detector
- Controller (Amplifier/linearization/signal processing)
The specifications of the lens decisively determine the optical path of the infrared thermometer, which is char-
acterized by the ratio Distance to Spot size.
The spectral filter selects the wavelength range, which is relevant for the temperature measurement. The
emitted infrared radiation is transformed into electrical signals by the detector and the controller.
