ηχομείωση → sound reduction
μείωση θορύβου → noise reduction, noise attenuation, noise abatement, sound abatement, noise control, sound control, noise mitigation
The sound reduction index is used to measure the level of sound insulation provided by a structure such as a wall, window, door, or ventilator. It is defined in the series of international standards ISO 16283 (parts 1-3) and the older ISO 140 (parts 1-14), or the regional or national variants on these standards. In the United States, the sound transmission class rating is generally used instead. The basic method for both the actual measurements and the mathematical calculations behind both standards is similar, however they diverge to a significant degree in the detail, and in the numerical results produced.
https://en.wikipedia.org/wiki/Sound_reduction_index#targetText=The%20sound%20reduction%20index%20is,national%20variants%20on%20these%20standards.
Noise reduction is the process of removing noise from a signal.
All signal processing devices, both analog and digital, have traits that make them susceptible to noise. 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.
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. These agitated electrons rapidly add and subtract from the voltage of the output signal and thus create detectable noise.
In the case of photographic film and magnetic tape, noise (both visible and audible) is introduced due to the grain structure of the medium. In photographic film, the size of the grains in the film determines the film's sensitivity, more sensitive film having larger sized grains. In magnetic tape, the larger the grains of the magnetic particles (usually ferric oxide or magnetite), the more prone the medium is to noise.
To compensate for this, larger areas of film or magnetic tape may be used to lower the noise to an acceptable level.
Many noise reduction algorithms tend to alter signals to a greater or lesser degree. The local signal-and-noise orthogonalization algorithm can be used to avoid changes to the signals.
https://en.wikipedia.org/wiki/Noise_reduction#targetText=Noise%20reduction%20is%20the%20process,make%20them%20susceptible%20to%20noise.
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خفض الضجيج
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Reducció de soroll
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Odstranění šumu
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Rauschunterdrückungsverfahren
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Noise reduction
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Riduzione del rumore
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ノイズリダクション
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Шумопонижение
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