Thermal imaging to record the energy reflected by the earth's surface. Imaging is not the record reflected energy as in the imaging multi-spectral satellite other resources. The sensor used is a thermal sensor. This sensor is sensitive to thermal energy that radiates from the face of the earth. Thermal sensor using photo detector is very sensitive to photons in the direction of the contact surface. Basically, this thermal sensor measures the temperature of the target surface.
Terrentang thermal energy in the spectrum of 3 μm to 15 μm. Recording the spectrum is divided into two parts, namely the range of 3 μm to 5 μm and 8 μm to 14 μm due to absorption and scattering consideration of atmospheric factors.
Thermal imaging usually have IFOVs (Instantaneous Field of Views) or wide field imaging scope. This is intended to ensure the amount of radiant energy received by the sensor is sufficient in the recording process. Therefore, this thermal image recording results usually have a more coarse spatial resolution than the multispectral image in visible and infrared reflection spectrum.
Thermal imaging can be performed on the day or night. Recorded on the imaging energy is the energy emitted from the surface of the target and not a reflection of energy such as recording image visible and infrared reflection spectrum. Thus the energy is independent of the reflection of sunlight at the time of recording. Thermal image widely used in various fields such as military, disaster relief, control of forest fires, and others.