IndexPhysics of ThermographyTypes of ThermographyMedical ThermographyLimitationsThermographic CamerasInfrared thermography is a non-contact imaging technique for imaging infrared radiation. The IR radiation emitted by an object has different intensity depending on its surface temperature. An IR camera detector detects IR radiation and electronically displays a visual image of temperatures: a thermal image or thermogram. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Since according to the law of black-body radiation, all objects with a temperature above absolute zero emit infrared radiation, thermography makes it possible to see your surroundings with or without visible illumination. The amount of radiation emitted by an object increases with temperature; therefore thermography allows you to see temperature variations. When viewed through a thermal imager, warm objects stand out well against cooler backgrounds. There are three types of thermography: liquid crystal thermography (LCT), infrared thermography (IRT), and microwave thermography (MWT). The non-invasive characteristics and high resolution of thermographic systems make them valuable diagnostic as well as therapeutic aids. Before 1800, the existence of the infrared portion of the electromagnetic spectrum was not even suspected. The original significance of the infrared spectrum as a form of thermal radiation is perhaps less evident today than it was at the time of its discovery in 1800 by Sir William Herschel during his search for a new optical material.Sir William Herschel (1738-1822 ), astronomer royal to King George III of England – and already famous for his discovery of the planet Uranus – was looking for an optical filter material to reduce the brightness of the image of the Sun in telescopes during solar observations. As the blackened thermometer was slowly moved along the colors of the spectrum, the temperature readings showed a steady increase from the purple to the red end. The Italian researcher Landriani, in a similar experiment in 1777, had observed more or less the same effect. It was Herschel, however, who first recognized that there must be a point at which the heating effect reaches a maximum, and that measurements limited to the visible portion of the spectrum failed to locate this point. When Herschel revealed his discovery, he referred to this new portion of the electromagnetic spectrum as the "thermometric spectrum." He sometimes called the radiation itself “dark heat” or simply “invisible rays.” “However, Herschel did not coin the term “infrared.” The word only began to appear in print about 75 years later, and it is still unclear who originated it. In the late 1950s and 1960s, Texas Instruments, Hughes Aircraft, and Honeywell developed single-element detectors that scanned scenes and produced images of lines. The military had control over the technology because it was expensive and had sensitive military applications. These basic detectors led to the development of modern thermal imaging. The pyroelectric vidicon tube was developed in the 1970s by Philips and EEV and became the core of a product first used by the Royal Navy for firefighting on board ships. In 1978, the research and development group at Raytheon, then part of Texas Instruments, patented ferroelectric infrared detectors that used barium strontium titanate, or BST, which is the material that coats the thermal imager's sensor. Raytheon first demonstrated the technology to the military in 1979. In the late 1980s, the governmentThe federal government has awarded contracts for the development of high-density arrays, or HIDADs, to both Raytheon and Honeywell to develop thermal imaging technology for practical military applications. Raytheon continued to commercialize BST technology. Honeywell developed vanadium oxide (VOx) microbolometer technology. Later, federal programs such as LOCUSP (Low-Cost Uncooled Sensor Program), provided funding for both companies to develop their thermal imaging technologies into equipment systems, including rifle scopes and driver visors. After the 1991 Gulf War, production volumes increased and costs decreased, so the use of thermal imaging was introduced into municipal fire services. In late 2004, Raytheon's commercial infrared division was sold to L-3 Communications. Meanwhile, the Honeywell micro bolometer obtained a patent in 1994. Boeing, Lockheed-Martin (which sold its infrared business to British Aerospace, or BAE), and others licensed VOx technology from Honeywell developed infrared detectors for military applications. Thermal imaging cameras based on both BST and micro bolometer technology are now available for non-military applications. In fact, thermal imaging has expanded for use in law enforcement, commercial and industrial applications, security, transportation, and many other industries. Bullard introduced its first thermal imager designed specifically for firefighting in 1998. The American Society of Non-Destructive Testing developed and approved standards for teaching thermography courses in 1992. These classes are called Level I, II and III. In the early 2000s, prices for infrared cameras continued to drop and thermal imaging cameras became smaller and smaller, so new uses for the construction industry began to emerge in earnest. In 2006, thermal imaging using infrared cameras by home inspectors and contractors became more common. In 2008, the International Association of Certified Home Inspectors – InterNACHI – developed its Infrared-Certified® program to teach home inspectors how to use infrared cameras in the wide variety of building inspection applications. Since then, InterNACHI has been the leading home inspector association promoting and teaching its members the effective use of thermography. Physics of Thermography Infrared ray is a type of electromagnetic wave with a frequency higher than radio frequencies and lower than those of visible light. The infrared region of the electromagnetic spectrum is usually considered to be between 0.77 and 100 μm for convenience, it is often divided into near infrared (0.77 to 1.5 μm), mid infrared (1.5 to 6 μm) and far infrared (60-40μm) and far infrared (40 to 100μm) Infrared rays are radiated spontaneously by all objects having a temperature above absolute zero (-459.67). The black body radiation law is the actual principle that works on thermography. A blackbody is an idealized physical body that absorbs all incident electromagnetic radiation. Thanks to this perfect absorption at all wavelengths, a blackbody is also the best possible emitter of thermal radiation, radiating incandescently in a characteristic spectrum and continuous which depends on body temperature. Thermal images, or thermograms, are actually visual displays. of the amount of infrared energy emitted, transmitted, and reflected by an object. Because there are multiple sources of infrared energy, it is difficult to obtain an accurate temperature of an object using this method. A thermal imaging camera is capable