What is Infrared Thermography, and how does it work?
The Electromagnetic Spectrum
A hypothetic body that completely absorbs all wavelengths of thermal radiation incident on it. Such bodies do not reflect light, and therefore appear black if their temperatures are low enough so as not to be self-luminous. All blackbodies heated to a given temperature emit thermal radiation with the same spectrum, as required by arguments of classical physics involving thermal equilibrium. However, the distribution of blackbody radiation as a function of wavelength, known as the Planck law, cannot be predicted using classical physics. This fact was the first motivating force behind the development of quantum mechanics.
Radiation Parameters of Objects
- - Emissivity(ε) : ability of an object to emit infrared radiation
- - Absorption(α) : ability of an object to absorb infrared radiation
- - Transmissivity(τ) : ability of an object to transmit infrared radiation
- - Reflectivity(ρ) : ability of an object to reflect infrared radiation
Thermal Imaging Camera
Thermal Imaging Camera
- Thermal imaging cameras don’t actually see temperature. Instead, they capture the infrared (IR) energy transfer from an object to its environment and produce a real-time image in a colour palette where hotter objects appear brighter and cooler objects appear darker.
- IR energy is generated by the vibration of atoms and molecules and behaves similarly to visible light where it can be reflected, refracted, absorbed and emitted. The more these atoms and molecules move, the higher the temperature of the object.
Amorphous silicon (a-Si) presents attractive electrical properties for microbolometer applications. It is easy to deposit uniformly on a 200mm CMOS substrate and is fully compatible with silicon microelectronics technology. Semiconductor electrical resistance is sensitive to temperature and to the activation energy, which is a property of the material.
Schematic of an un-cooled thermal detector pixel.
Thermal Camera Applications
- Thermal imaging cameras are becoming a common tool in the home inspection industry where they are being used to verify building performance to specifications, to determine insulation condition, locate leaks, verify structure design and locate moisture intrusion.
- Thermal imaging cameras are used where the identification of thermal patterns can be used to find something or diagnose a condition, such as poor insulation in a home or an overloaded electrical circuit.
- Some examples of thermal imaging camera applications include :
- Substation electrical inspections – Thermal heat loss inspections of buildings
- Locate radiant heating wires or pipes – Locate potential areas for mold growth
- Flat-roof leak detection for buildings
- Detect thermal patterns on boiler tubes
- Mechanical bearing inspections
- Detect insulation leaks in refrigeration equipment
- Detect any places with problems on walls or in structures/ Inspect architectural structures for safety
- Detect any problems associated with energy consumption, humidity and electricity inside buildings
- Safety inspection for gas leaks
- Check for the overheating or cooling of electric or electronic devices
Check for the overheating of transmission lines and transforming system
- Inspect and analyze the distribution condition of pipelines
- Check for any deterioration in firebricks in the industrial furnace
- Measure temperature of components for automobiles and aircrafts
- Check for any deterioration in plant machinery and electric components
- Identify any defective products in the manufacturing process for electronic products
- Mange heat distribution in chemical tank/ Manage heat distribution in rolling process
- Detect and diagnose any metal fatigue
- Non-destructive inspection
- Our security customers benefit from thermal imaging cameras because they help them to secure facilities like ports, airports, nuclear facilities, warehouses, estates and many more against intruders.
- Remain vigilant for any intruders entering factory facilities, Maintain a fire watch
- Remain vigilant for any intruders entering plants and substations
- Border watch, Coast watch and Smuggling watch
- System to prevent crashes during night voyages
- Safe night driving of trains and vehicles
- Closely observe the night taking off and landing of aircrafts
The emissivity of a material (usually written ε or e) is the relative ability of its surface to emit energy by radiation.
It is the ratio of energy radiated by a particular material to energy radiated by a black body at the same temperature.
A true black body would have an ε = 1 while any real object would have ε < 1. Emissivity is a dimensionless quantity.
Paint Emissivity shown in rough figures depends on the surfaces.