When the object of absorption rate α = 1, then that object can absorb all of the projection to the thermal radiation of various wavelengths, this object is called an absolute black body, or simply blackbody (black body). Blackbody thermal radiation is absorbed by the strongest of an idealized object, the actual object is not absolute black. However, theoretical studies can be designed in a variety of absolute black. For example: There is a hollow container, the wall by the opaque material, the wall of opening a small hole, so you can form a black body. Because when the rays launched into the hole, it will be multiple reflections in the cavity, the inner wall of each reflector surface to absorb part of the energy, if the aperture to open a small hole, far less than the surface area of the container . This radiation can be considered to be holes all absorbed. Holes can be considered to be absolute black. Absolute black body emissivity of 1. General objects received radiation, the radiation energy is always there absorption, reflection. Absorbed as part of the share of total energy absorption coefficient, its value between 0 and 1. Absorption capacity of the black color of the object is greater than the white color of the objects, the absorption coefficient is relatively large. If the absorption coefficient of 1 means that all energy is absorbed without reflection. With this capability objects called black body. There is no absolute black body in nature. Absolutely black body is an idealized reference model. In the thermal infrared remote sensing scanner system equipped with high temperature and low temperature blackbody blackbody as a reference to detect features in thermal radiation source. Functional absolutely black body is made by the artificial method. Generally speaking, the object of the radiation energy and its surface temperature, the higher the temperature, the greater the radiation energy. In other words, the object of the radiation with the temperature, the spectral distribution of radiation also changes.