4.2.2 Chroma and luminance noise separation.3.2 Dynamic noise limiter and dynamic noise reduction.3.1 Compander-based noise reduction systems.To compensate for this, larger areas of film or magnetic tape may be used to lower the noise to an acceptable level. In magnetic tape, the larger the grains of the magnetic particles (usually ferric oxide or magnetite), the more prone the medium is to noise. In photographic film, the size of the grains in the film determines the film's sensitivity, more sensitive film having larger sized grains. In the case of photographic film and magnetic tape, noise (both visible and audible) is introduced due to the grain structure of the medium. These agitated electrons rapidly add and subtract from the voltage of the output signal and thus create detectable noise. In electronic recording devices, a major type of noise is hiss created by random electron motion due to thermal agitation at all temperatures above absolute zero. Noise can be random or white noise with an even frequency distribution, or frequency-dependent noise introduced by a device's mechanism or signal processing algorithms. Noise reduction algorithms may distort the signal to some degree.Īll signal processing devices, both analog and digital, have traits that make them susceptible to noise. Noise reduction techniques exist for audio and images.
Noise reduction is the process of removing noise from a signal. For the noise reduction of machinery and products, see noise control. For the reduction of a sound's volume, see soundproofing.
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