21. Active thermography uses an external source for measured object excitation, that means introducing an energy into the object. 22. But beware : Some printers try to pass off thermography as engraving by calling it engravo-printing or thermograving. 23. Firefighters use thermography to see through smoke, to find persons, and to localize the base of a fire. 24. Passive thermography has many applications such as surveillance of people on a scene and medical diagnosis ( specifically thermology ). 25. Although it lacks the fineness and distinctiveness of engraving, thermography is a less expensive method of achieving raised type. 26. Infrared ( IR ) thermography is an analysis technique based on the detection of radiation in the IR wavelength spectrum. 27. If an artificial excitation using an external source is applied on the measured object, it is called active thermography . 28. It is also fitted in the US Army's MTI system, along with an optical and an thermography imager. 29. Maintenance technicians use thermography to locate overheating joints and sections of power lines, which are a sign of impending failure. 30. Building envelope thermography involves using an infrared camera to view temperature anomalies on the interior and exterior surfaces of the structure.
