Spectral Infrared Thermography
Spectral thermography provides material specific precision measurements
- Concentrate measurements on highly emissive or transmissive spectral ranges
- Thermography on glass and through glass as well as temperature measurements through gases or even gas flames with spectral filters
- Detection of various gases
- Recording of temperatures and characterization of large-scale flames
- Filters close to the detector of the infrared camera avoid warm aperture effects
Associated Thermographic Automation Solutions
Advantages of this Thermography Solutions in this Application
Wide Range of Spectral Filters for Mounting Close to the Detector
InfraTec offers a wide range of special spectral filters for thermographic measurement of the most different materials and applications. Those filters can also be customized. Both the infared camera systems of the ImageIR ® series as well as the long-wave uncooled VarioCAM ® hr head cameras provide facilities for a mounting close to the detector within a filter wheel or a filter slider. The filter wheel of the ImageIR ® models is especially convenient as filters can be changed remotely controlled and motorized. Warm aperture effects caused by a filter position in front of the lens and resulting in possibly big measurement errors can be avoided by such positioning close to the detector being possible in infrared camera systems of InfraTec.

Applications of Spectral Thermography
Besides the "on-glass" and "through-glass" measurement exists a number of other applications in different industrial sectors as well as in the field of research and development:
- IR-reflectography
IR-reflectography is used for the detection of lower painting layers due to its spectral behaviour (upper layer transmissive, lower drawings reflective).
- Humidity detection
With the help of humidity detection, for example for the analysis of building materials in case of claims, the spectral absorption factor of water band is defined.
- Leakage
Another interesting application is the detection of leakages on tanks using IR-detectable gases. A suitable and available gas is CO2, having a strong absorption band at 4,25 μm. A tempered background helps to recognize the leaving gas flow.
- Temperature measurement of flames
Temperature of flames can be estimated by measuring selectively within the absorption band of CO2 at 4.25 μm. Thermography at objects behind the flame is possible using the spectral range of (3.75 … 4) μm (for example furnace walls or pipes).
- Film extrusion process
Film surface temperature can be measured using a band pass filter at 3.4 μm (applicable for various plastics, e.g. polyethylene, polypropylene, polyamide, polyvinyl). For some plastics an absorption band at 8 μm (LWIR) can be used.