Fundamentals of Radiative Heat Flow and Radiation Exchange at the Target Surface in Thermal Imaging or Thermography

Fundamentals of Radiative Heat Flow and Radiation Exchange at the Target Surface in Thermal Imaging or Thermography

Infrared thermography is a powerful non-contact temperature measurement technique widely used in industrial condition monitoring, electrical inspections, mechanical diagnostics, building energy audits, and research applications. The foundation of thermography lies in the understanding of radiative heat transfer, particularly the way infrared radiation interacts with surfaces. In thermographic inspections, the surface being observed by the thermal camera is known as the target surface and the radiation leaving or arriving at this surface determines the temperature measurement obtained by the instrument. To fully understand thermography and interpret thermal images correctly, it is essential to understand how infrared radiation is emitted, reflected, transmitted and absorbed at the target surface. These interactions govern the energy balance at the surface and influence the accuracy of temperature measurements. Infrared Radiation and Non-Contact Temperature Measurement All objects with a t…