Infrared Thermography

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Infrared measurement techniques are based on the principle that every physical body with a temperature above 0K emits energy in the form of electromagnetic radiation. Electromagnetic radiation in the wavelength range between 0,78μm to 1000µm is assigned to the infrared radiation spectrum and also referred to as heat radiation. Infrared radiation can be characterized by its wavelength into different electromagnetic spectrums:

Infrared spectrum (IR)

Wavelength / µm

Near IR

0,78 to 1,40

Short wavelength IR

1,40 to 3,00

Mid wavelength IR

3,00 to 8,00

Long wavelength IR

8,00 to 15,00

Far IR

15,00 to 1.000

Measuring techniques as pyrometry and infrared-thermography (or IR-thermography ) use the emitted radiation of each body, to determine noninvasive the associated surface temperature. Pyrometers measure time dependent and thermography cameras determine in addition locally resolved surface temperatures. The theoretical temperature range of cooled thermal imaging cameras is from -30°C up to several 1000 °C. The repeatability of a measurement under optimal conditions is less than 1K and the minimum resolvable temperature below 25mK. The maximum optical resolution reaches up to 10µm/pixel and the temporal resolution is up to 3200Hz. The accuracy of each temperature measurement depends on a variety of parameters, such as optical resolution, the integration time (similar to an exposure time), the frame rate, the temperature range and the surface material and its condition.

Measurement techniques

  • Pyrometry, 2-Color- Pyrometry
  • highspeed IR-Thermography in medium and long IR wavelength

Measured Variable

Digital level