A night vision device (NVD) is an optical instrument that allows images to be produced in levels of light approaching total darkness. They are most often used by the military and law enforcement agencies, but are available to civilian users. The term usually refers to a complete unit, including an image intensifier tube, a protective and generally water-resistant housing, and some type of mounting system. Many NVDs also include sacrificial lenses, IR illuminators, and telescopic lenses.
Night vision devices were first used in World War II, and came into wide use during the Vietnam War. The technology has evolved greatly since their introduction, leading to several "generations" of night vision equipment with performance increasing and price decreasing. Another term is "night optical device" or NOD.
Read more about Night Vision Device: Generations, Figure of Merit, Other Technologies, Legality, US Patents
Famous quotes containing the words night, vision and/or device:
“They threw off their clothes, and he gathered her to him, and found her, found the pure lambent reality of her for ever invisible flesh. Quenched, inhuman, his fingers upon her unrevealed nudity were the fingers of silence upon silence, the body of mysterious night upon the body of mysterious night, the night masculine and feminine, never to be seen with the eye, or known with the mind, only known as a palpable revelation of living otherness.”
—D.H. (David Herbert)
“I’ve been cursed for delving into the mysteries of life. Perhaps death is sacred, and I’ve profaned it. Oh, what a wonderful vision it was. I dreamed of being the first to give to the world the secret that God is so jealous of, the formula for life. Think of the power, to create a man. And I did, I did it, I created a man. And who knows, in time I could have trained him to do my will. I could have bred a race, I might even have found the secret of eternal life.”
—William Hurlbut (1883–?)
“The man who pretends that the distribution of income in this country reflects the distribution of ability or character is an ignoramus. The man who says that it could by any possible political device be made to do so is an unpractical visionary. But the man who says that it ought to do so is something worse than an ignoramous and more disastrous than a visionary: he is, in the profoundest Scriptural sense of the word, a fool.”
—George Bernard Shaw (1856–1950)