Thermal imagers detect heat patterns in the infrared wavelength spectrum.  Thermal imagers rely on the emission of thermal or infrared energy by all objects above 0 Kelvin. They detect energy emissions (heat) in the infrared wavelength spectrum of 1 micron to 100 microns.  Thermography, thermology, thermal wave imaging, thermovision and thermal infrared night vision use thermal imagers, some of the actual devices appear like slightly oversized video cameras, while others appear a bit bulkier. They have been getting smaller since the introduction of Focal Plane Array (FPA) detectors.  The specific uses of the imagers are widespread. Several major cost saving uses depend upon the temperature measurement capability of the specific imaging equipment and a great many commercial and industrial uses produce significant cost savings or cost avoidance.  Thermal imaging devices provide the observer with instruments that can collect ( just like a video or still camera) and convert the thermal infrared radiation emitted (and also reflected) by objects into images that can be seen on a view screen or computer display.