detection la gi

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In general, detection is the action of accessing information without specific cooperation from with the sender.

In the history of radio communications, the term "detector" was first used for a device that detected the simple presence or absence of a radio signal, since all communications were in Morse code. The term is still in use today to lớn describe a component that extracts a particular signal from all of the electromagnetic waves present. Detection is usually based on the frequency of the carrier signal, as in the familiar frequencies of radio broadcasting, but it may also involve filtering a faint signal from noise, as in radio astronomy, or reconstructing a hidden signal, as in steganography.

In optoelectronics, "detection" means converting a received optical input to lớn an electrical output. For example, the light signal received through an optical fiber is converted to lớn an electrical signal in a detector such as a photodiode.

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In steganography, attempts to lớn detect hidden signals in suspected carrier material is referred to lớn as steganalysis. Steganalysis has an interesting difference from most other types of detection, in that it can often only determine the probability that a hidden message exists; this is in contrast to lớn the detection of signals which are simply encrypted, as the ciphertext can often be identified with certainty, even if it cannot be decoded.

In the military, detection refers to lớn the special discipline of reconnaissance with the aim to lớn recognize the presence of an object in a location or ambiance.

Finally, the art of detection, also known as following clues, is the work of a detective in attempting to lớn reconstruct a sequence of events by identifying the relevant information in a situation.

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See also[edit]

  • Object detection
  • Signal detection theory