Every object has a distinct heat signature. An object’s infrared radiation is used in thermal imaging to improve the visibility of objects in the dark. Thermal imaging receptors detect an objects rendition and create an image based on that information. Thermal imaging can penetrate any obscurants such as smoke, haze, and fog. Thermal imaging works for Maintenance & Repair without ambient light since it detects the heat signature of an object.
It uses a thermal camera (Thermal imager) which is a heat sensor that is capable of detecting the slightest differences in temperature.