Radiation detection, thermography

Another technique utilizing radiation from an object as a means of measuring its temperature is that of thermography, that is, the mapping of surface temperature distributions over extended areas. This is fairly widely used in the medical field for the detection of tumors near the surface of the skin and in industrial applications for detection of hot spots, such as defective insulators on power lines, defects in furnace walls, and areas of heat leaks in buildings. Usually, comparison measurements, rather than the actual determinations of temperature values, are made in thermography. Resolutions of 0.05°C to 0.1 °C are attainable under the best conditions. 

The technique of infrared thermography relies upon the detection of infrared radiation emitted from the surface of a structure. An infrared scanning unit converts electromagnetic thermal energy radiated from an object into electronic video signals and produces color-coded maps of isotherms (64). Differences in thermal waves on the surface of a material can be detected that will make certain flaws visible and allow detection of flaws with low-temperature differentials with respect to the surrounding area within... 

Infrared (IR) thermography is a nonintrusive, two-dimensional technique for the whole-field measurement of surface temperature. An infrared scanning radiometer (IRSR) detects the electromagnetic energy radiated in the IR spectral band by the surface of interest and converts it into an electronic signal. For an object whose surface temperature is T, the monochromatic radiation of intensity Ex emitted by the surface can be written using Planck s law as... 

---