HELICOPTERS |
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A helicopter is an aircraft which is lifted and propelled by one or more horizontal rotors (propellers). Helicopters are classified as rotary-wing aircraft to distinguish them from conventional fixed-wing aircraft. The word helicopter is derived from the Greek words helix (spiral) and pteron (wing). The engine-driven helicopter was invented by the Slovak inventor Jan Bahyl. The first stable, single-rotor, fully-controllable helicopter to enter large full-scale production was made by Igor Sikorsky in 1942.
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PHOTOGRAPHY |
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Photography is the process of making pictures by means of the action of light. It involves recording light patterns, as reflected from objects, onto a sensitive medium through a timed exposure. The process is done through mechanical, chemical or digital devices commonly known as cameras.
The word comes from the Greek words φως phos ("light"), and γραφις graphis ("stylus", "paintbrush") or γραφη graphê, together meaning "drawing with light" or "representation by means of lines" or "drawing." Traditionally, the product of photography has been called a photograph. The term photo is a convenient abbreviation. Many people also call them pictures. In digital photography, the term image has begun to replace photograph. This term is neither more nor less correct than photograph, either in film or digital photography. (The term image is traditional in geometric optics.)
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VIDEO - SURVEILANCE |
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The use of video surveilance technology to enhance privacy, protect human or property.
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