Noise (spectral phenomenon)

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Noise refers to many types of random, troublesome, problematic, or unwanted signals.

Acoustic noise may mar aesthetic experience, such as attending a concert hall. It may also be a medical issue inherent in the biology of hearing.

In technology, noise is unwanted signals in a device or apparatus, commonly of an electrical nature. The nature of noise is much studied in mathematics and is a prominent topic in statistics.

This article provides a survey of specific topics linked to their primary articles.

Acoustic noise

In transportation

Other acoustic noise

Noise in biology

Noise in computer graphics

Noise in computer graphics refers to various pseudo-random functions used to create textures, including:

  • Gradient noise, created by interpolation of a lattice of pseudorandom gradients
  • Simplex noise, a method for constructing an n-dimensional noise function comparable to Perlin noise
  • Simulation noise, a function that creates a divergence-free field
  • Value noise, created by interpolation of a lattice of pseudorandom values; differs from gradient noise
  • Wavelet noise, an alternative to Perlin noise which reduces problems of aliasing and detail loss
  • Worley noise, a noise function introduced by Steven Worley in 1996

Noise in electronics and radio

Noise in mathematics

  • Any one of many statistical types or colors of noise, such as
    • White noise, which has constant power spectral density
    • Gaussian noise, with a probability density function equal to that of the normal distribution
    • Pink noise, with spectral density inversely proportional to frequency
    • Brownian noise or "brown" noise, with spectral density inversely proportional to the square of frequency
  • Pseudorandom noise, in cryptography, artificial signal that can pass for random
  • Statistical noise, a colloquialism for recognized amounts of unexplained variation in a sample
  • Shot noise, noise which can be modeled by a Poisson process
  • Noise-based logic, where logic values are different stochastic processes
  • Noise print, a statistical signature of ambient noise, used in its suppression

Other types of noise

Measures of noise intensity

See also