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LIDAR scanning is a means of detecting an object's characteristics using beams of light from a laser. LIDAR, an acronym for light detection and ranging, works on a similar principle to that of radar, except that instead of emitting radio waves it uses ultraviolet, near-infrared, or visible light. In LIDAR scanning, the laser fires a pattern of light pulses at the target, and when light reflects back from the target, its properties are analyzed, giving information about the object that reflected it. LIDAR scanning has been used in a number of areas, including meteorology, geology, and movies.
LIDAR is extremely useful for many applications because it uses electromagnetic radiation with much shorter wavelengths than radar. Photons of visible and ultraviolet light have wavelengths of only a few hundred nanometers, while radio emissions have a wavelength of at least 1 millimeter, and most modern radars emit radio waves with wavelengths of at least 10 millimeters. A detection system based on emitting electromagnetic radiation generally cannot detect objects smaller than the wavelength of its own emissions, and so LIDAR is effective for tasks that require detection of small objects or details. LIDAR is also more effective than radar for detecting nonmetallic objects, which often reflect radio waves poorly and in some cases do not reflect them at all.
LIDAR scanning is commonly used by meteorologists to study atmospheric conditions and weather patterns. Several different methods exist, making it possible to use LIDAR to detect things such as clouds, the chemical composition of an area of the atmosphere, or wind speed. This information is used for purposes such as weather tracking and prediction and monitoring wind conditions around electricity-generating wind turbines so that the turbines can be adjusted to maximize power output and prevent damage to equipment.
LIDAR scanning can also be used to study the Earth's topography for fields such as geology, seismology, and archeology. LIDAR can produce very high-resolution maps of the Earth due to its ability to detect small or subtle terrain features, discern small differences in elevation and small changes in it over time, and accurately scan terrain covered by dense vegetation. This allows geologists to study subtle changes in the Earth's surface. The movement of geological faults and glaciers, both of which move at extremely slow rates, can also be measured this way. LIDAR scanning can also be used to detect subtle features and changes in soil, making it useful for soil surveys.
LIDAR scanning can also provide three-dimensional imaging in other areas. A LIDAR-based device called a time-of-flight 3-D laser scanner creates a three-dimensional image of an object in much the same way that LIDAR is used to measure topography, bombarding the object with rapid pulses of light and measuring how long it takes for the reflected photons to return. This can produce an accurate image more quickly than some of the other forms of three-dimensional imaging. LIDAR is used in this way for purposes such as measurement and quality control in industry; the creation of 3-D images and models for movies, television, and video games; and precise examination of historical artifacts and artwork.