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Method Name: |
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Ground infrared thermography |
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Method Type: |
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Thermic Methods
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Assigned Problems: |
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Principle: |
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Determination of ground temperature using infrared surface temperature measurements (thermal / infrared radiation; remote sensing) or temperature testing probes (resistance thermometer; requires contact with object) |
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Keywords: |
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Thermal imaging; infrared measurements; thermal and infrared radiation; temperature distribution |
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Prerequisites: |
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- Existence of thermal contrast
- Infrared radiation measurements should be conducted during night (preferentially shortly before sunrise)
- Thermal influences by cars (measuring car, if device is truck-mounted) and other heat sources
- Measurements within shallow depths may need corrections for daily temperature variations (ground testing probes)
- The field of view of radiation-measurement devices is limited
- Weather / climate conditions: images may be difficult to interpret if recorded over snow-covered areas, wet ground, frost or during rain or high wind
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Resolution: |
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Radiation measurements (infrared thermography): Thermal resolution: usually ± 0,03° K; spatial / geometrical resolution: usually 1,5 mrad
Resistance thermometers: Thermal resolution: ± 0,03° K
The typical depth of investigation: Surface (infrared radiation measurements) or first few m (ground temperature testing probes). |
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Expected Results: |
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- Measured parameter: Infrared thermography measures the intensity of the emitted electromagnetic radiation of a body; Resistance thermometer measures the electric resistance that is directly related to temperature (in °K or °C)
- Data analysis: The measured signal may then be converted to temperature (emission coefficient/ emissivity must be known)
- Interpretation: Infrared thermography: Qualitative interpretation of relative thermal anomalies assuming that the measured signal (intensity of electromagnetic radiation) is correlated to the true temperature
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Combination with other Methods: |
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- Required additional information: camera information / setup (valuable wavelength, etc.), weather conditions, camera position (for processing / interpretation)
- Related add-on information: depending on problem set ( e.g., geological information)
- Independent additional information: georadar
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Operating Expense: |
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- Crew size: 1 key person; 1 - 2 assistants
- Acquisition speed: several measurements per hour
- Processing: 1 - 2 days per measuring day
- Equipment rental costs: intermediate
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Parameters to specify: |
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- Instrument type
- Measuring grid / continuous measurements (acquisition speed!)
- Height of sensor / field of view
- Resolution and accuracy
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QC Documents: |
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- Field notes (e.g., all activities, effective time schedule, present personnel)
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Products: |
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- Map / images (or profiles) of temperature distribution
- Interpretation
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