Noise in the context of PSNR

Habituation is a form of non-associative learning in which an organism’s non-reinforced response to an inconsequential stimulus decreases after repeated or prolonged presentations of that stimulus. For example, organisms may habituate to repeated sudden loud noises when they learn that these have no consequences.

Habituation can occur in responses that habituate include those that involve an entire organism or specific biological component systems of an organism. The broad ubiquity of habituation across all forms of life has led to it being called "the simplest, most universal form of learning...as fundamental a characteristic of life as DNA." Functionally, habituation is thought to free up cognitive resources for other stimuli that are associated with biologically important events by diminishing the response to inconsequential stimuli.

Repetition is important in music, where sounds or sequences are often repeated. It may be called restatement, such as the restatement of a theme. While it plays a role in all music, with noise and musical tones lying along a spectrum from irregular to periodic sounds, it is especially prominent in specific styles.

Noise music (or simply noise) is a subgenre of experimental music that is characterised by its use of unwanted noise as a primary musical element. The genre has roots in early 20th century avant-garde music, but later drew influence from industrial music. It is characterized by a rejection of conventional music theory and traditional song structures, often featuring little or no melody, rhythm, or harmony. This type of music tends to challenge the conventional distinction between musical and non-musical sound.

"Noise as music" originated as an avant-garde music style in the 1910s through the work of Luigi Russolo an Italian Futurist, who published the manifesto The Art of Noises in 1913. Elements of noise music were later explored by artists in the Dada and Fluxus movements, as well as through electroacoustic music, modern classical and musique concrète. Composers such as John Cage, Edgard Varèse and James Tenney would explicitly use the term "noise" to describe some of their experimental practices. During the 1960s and 1970s, compositions such as Robert Ashley's "The Wolfman" (1964) and Pauline Oliveros "A Little Noise In The System" (1967) were among the earliest examples of contemporary noise music. While works by non-academic artists such as Lou Reed's Metal Machine Music were influential for later noise artists.

Background noise or ambient noise is any sound other than the sound being monitored (primary sound). Background noise is a form of noise pollution or interference. Background noise is an important concept in setting noise levels.

Background noises include environmental noises such as water waves, traffic noise, alarms, extraneous speech, bioacoustic noise from animals, and electrical noise from devices such as refrigerators, air conditioning, power supplies, and motors.

Noise pollution, or sound pollution, is the propagation of noise or sound with potential harmful effects on humans and animals. The source of outdoor noise worldwide is mainly caused by machines, transport and propagation systems. Poor urban planning may give rise to noise disintegration or pollution. Side-by-side industrial and residential buildings can result in noise pollution in the residential areas. Some of the main sources of noise in residential areas include loud music, transportation (traffic, rail, airplanes, etc.), lawn care maintenance, construction, electrical generators, wind turbines, explosions, and people.

Documented problems associated with noise in urban environments go back as far as ancient Rome. Research suggests that noise pollution in the United States is the highest in low-income and racial minority neighborhoods, and noise pollution associated with household electricity generators is an emerging environmental degradation in many developing nations.

An occupational injury is bodily damage resulting from working. The most common organs involved are the spine, hands, the head, lungs, eyes, skeleton, and skin. Occupational injuries can result from exposure to occupational hazards (physical, chemical, biological, or psychosocial), such as temperature, noise, insect or animal bites, blood-borne pathogens, aerosols, hazardous chemicals, radiation, and occupational burnout.

While many prevention methods are set in place, injuries may still occur due to poor ergonomics, manual handling of heavy loads, misuse or failure of equipment, exposure to general hazards, and inadequate safety training.

Marine pollution occurs when substances used or spread by humans, such as industrial, agricultural, and residential waste; particles; noise; excess carbon dioxide; or invasive organisms enter the ocean and cause harmful effects there. The majority of this waste (80%) comes from land-based activity, although marine transportation significantly contributes as well. It is a combination of chemicals and trash, most of which comes from land sources and is washed or blown into the ocean. This pollution results in damage to the environment, to the health of all organisms, and to economic structures worldwide. Since most inputs come from land, via rivers, sewage, or the atmosphere, it means that continental shelves are more vulnerable to pollution. Air pollution is also a contributing factor, as it carries iron, carbonic acid, nitrogen, silicon, sulfur, pesticides, and dust particles into the ocean. The pollution often comes from nonpoint sources such as agricultural runoff, wind-blown debris, and dust. These nonpoint sources are largely due to runoff that enters the ocean through rivers, but wind-blown debris and dust can also play a role, as these pollutants can settle into waterways and oceans. Pathways of pollution include direct discharge, land runoff, ship pollution, bilge pollution, dredging (which can create dredge plumes), atmospheric pollution and, potentially, deep sea mining.

Different types of marine pollution can be grouped as pollution from marine debris, plastic pollution, including microplastics, ocean acidification, nutrient pollution, toxins, and underwater noise. Plastic pollution in the ocean is a type of marine pollution by plastics, ranging in size from large original material such as bottles and bags, down to microplastics formed from the fragmentation of plastic materials. Marine debris is mainly discarded human rubbish which floats on, or is suspended in the ocean. Plastic pollution is harmful to marine life.

Psychoacoustics is the branch of psychophysics involving the scientific study of the perception of sound by the human auditory system. It is the branch of science studying the psychological responses associated with sound including noise, speech, and music. Psychoacoustics is an interdisciplinary field including psychology, acoustics, electronic engineering, physics, biology, physiology, and computer science.

Noise control or noise mitigation is a set of strategies to reduce noise pollution or to reduce the impact of that noise, whether outdoors or indoors.

A hearing protection device, also known as a HPD, is an ear protection device worn in or over the ears while exposed to hazardous noise and provide hearing protection to help prevent noise-induced hearing loss. HPDs reduce the level of the noise entering the ear. HPDs can also protect against other effects of noise exposure such as tinnitus and hyperacusis. There are many different types of HPDs available for use, including earmuffs, earplugs, electronic hearing protection devices, and semi-insert devices.

The use of the HPD without individual selection, training and fit testing does not significantly reduce the risk of hearing loss. For example, one study covered more than 19 thousand workers, some of whom usually used hearing protective devices, and some did not use them at all. There was no statistically significant difference in the risk of noise-induced hearing loss.

High fidelity (hi-fi or, rarely, HiFi) is the high-quality reproduction of sound. It is popular with audiophiles and home audio enthusiasts. Ideally, high-fidelity equipment has inaudible noise and distortion, and a flat (neutral, uncolored) frequency response within the human hearing range.

High fidelity contrasts with the lower-quality lo-fi sound produced by inexpensive audio equipment, AM radio, or the inferior quality of sound reproduction that can be heard in recordings made until the late 1940s.

The Art of Noises (Italian: L'arte dei Rumori) is a Futurist manifesto written by Luigi Russolo in a 1913 letter to friend and Futurist composer Francesco Balilla Pratella. In it, Russolo argues that the human ear has become accustomed to the speed, energy, and noise of the urban industrial soundscape; furthermore, this new sonic palette requires a new approach to musical instrumentation and composition. He proposes a number of conclusions about how electronics and other technology will allow futurist musicians to "substitute for the limited variety of timbres that the orchestra possesses today the infinite variety of timbres in noises, reproduced with appropriate mechanisms".

The Art of Noises is considered by some authors to be one of the most important and influential texts in 20th-century musical aesthetics.

Noise-induced hearing loss (NIHL) is a hearing impairment resulting from exposure to loud sound. People may have a loss of perception of a narrow range of frequencies or impaired perception of sound including sensitivity to sound or ringing in the ears. When exposure to hazards such as noise occur at work and is associated with hearing loss, it is referred to as occupational hearing loss.

Hearing may deteriorate gradually from chronic and repeated noise exposure (such as loud music or background noise) or suddenly from exposure to impulse noise, which is a short high intensity noise (such as a gunshot or airhorn). In both types, loud sound overstimulates delicate hearing cells, leading to the permanent injury or death of the cells. Once lost this way, hearing cannot be restored in humans.

Musicality (music-al-ity) is "sensitivity to, knowledge of, or talent for music" or "the quality or state of being musical", and is used to refer to specific if vaguely defined qualities in pieces and/or genres of music, such as melodiousness and harmoniousness. These definitions are somewhat hampered by the difficulty of defining music, but, colloquially, "music" is often contrasted with noise and randomness. Judges of contest music may describe a performance as bringing the music on the page to life; of expressing more than the mere faithful reproduction of pitches, rhythms, and composer dynamic markings. In the company of two or more musicians, there is the added experience of the ensemble effect in which the players express something greater than the sum of their individual parts. A person considered musical has the ability to perceive and reproduce differences in aspects of music including pitch, rhythm, and harmony (see: ear training). Two types of musicality may be differentiated: to be able to perceive music (musical receptivity) and to be able to reproduce music in addition to creating music (musical creativity).

In computing, bandwidth is the maximum rate of data transfer across a given path. Bandwidth may be characterized as network bandwidth, data bandwidth, or digital bandwidth.

This definition of bandwidth is in contrast to the field of signal processing, wireless communications, modem data transmission, digital communications, and electronics, in which bandwidth is used to refer to the signal bandwidth measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power. The actual bit rate that can be achieved depends not only on the signal bandwidth but also on the noise on the channel.

Environmental noise is an accumulation of noise pollution that occurs outside. This noise can be caused by transport, industrial, and recreational activities.

Noise is frequently described as 'unwanted sound'. Within this context, environmental noise is generally present in some form in all areas of human, animal, or environmental activity. The effects in humans of exposure to environmental noise may vary from emotional to physiological and psychological. Noise at low levels is not necessarily harmful. Environmental noise can also convey a sense of liveliness in an area, which can be desirable. The adverse effects of noise exposure (i.e. noise pollution) could include: interference with speech or other 'desired' sounds, annoyance, sleep disturbance, anxiety, hearing damage and stress-related cardiovascular health problems.

In statistics and image processing, to smooth a data set is to create an approximating function that attempts to capture important patterns in the data, while leaving out noise or other fine-scale structures/rapid phenomena. In smoothing, the data points of a signal are modified so individual points higher than the adjacent points (presumably because of noise) are reduced, and points that are lower than the adjacent points are increased, leading to a smoother signal.

Reducing noise by smoothing may aid in data analysis in two notable ways:

A spoke card, or spokecard, is a card placed in the spokes of a bicycle wheel. They lie parallel to the entire wheel. Most spoke cards are laminated.

Throughout the 20th century, playing cards were placed in such a way as to make a noise as the card flaps against the spokes; however, there is no evidence that these were called "spoke cards."