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Machine Listening
Computer audition (CA) or machine listening is the general field of study of algorithms and systems for audio interpretation by machines. Since the notion of what it means for a machine to "hear" is very broad and somewhat vague, computer audition attempts to bring together several disciplines that originally dealt with specific problems or had a concrete application in mind. The engineer Paris Smaragdis, interviewed in ''Technology Review'', talks about these systems "software that uses sound to locate people moving through rooms, monitor machinery for impending breakdowns, or activate traffic cameras to record accidents." Inspired by models of human audition, CA deals with questions of representation, transduction, grouping, use of musical knowledge and general sound semantics for the purpose of performing intelligent operations on audio and music signals by the computer. Technically this requires a combination of methods from the fields of signal processing, auditory modellin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algorithm
In mathematics and computer science, an algorithm () is a finite sequence of rigorous instructions, typically used to solve a class of specific problems or to perform a computation. Algorithms are used as specifications for performing calculations and data processing. More advanced algorithms can perform automated deductions (referred to as automated reasoning) and use mathematical and logical tests to divert the code execution through various routes (referred to as automated decision-making). Using human characteristics as descriptors of machines in metaphorical ways was already practiced by Alan Turing with terms such as "memory", "search" and "stimulus". In contrast, a heuristic is an approach to problem solving that may not be fully specified or may not guarantee correct or optimal results, especially in problem domains where there is no well-defined correct or optimal result. As an effective method, an algorithm can be expressed within a finite amount of space ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Audio Texture
In music, texture is how the tempo, melodic, and harmonic materials are combined in a musical composition, determining the overall quality of the sound in a piece. The texture is often described in regard to the density, or thickness, and range, or width, between lowest and highest pitches, in relative terms as well as more specifically distinguished according to the number of voices, or parts, and the relationship between these voices (see Common types below). For example, a thick texture contains many 'layers' of instruments. One of these layers could be a string section or another brass. The thickness also is changed by the amount and the richness of the instruments playing the piece. The thickness varies from light to thick. A piece's texture may be changed by the number and character of parts playing at once, the timbre of the instruments or voices playing these parts and the harmony, tempo, and rhythms used. The types categorized by number and relationship of parts are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harmony
In music, harmony is the process by which individual sounds are joined together or composed into whole units or compositions. Often, the term harmony refers to simultaneously occurring frequencies, pitches ( tones, notes), or chords. However, harmony is generally understood to involve both vertical harmony (chords) and horizontal harmony (melody). Harmony is a perceptual property of music, and, along with melody, one of the building blocks of Western music. Its perception is based on consonance, a concept whose definition has changed various times throughout Western music. In a physiological approach, consonance is a continuous variable. Consonant pitch relationships are described as sounding more pleasant, euphonious, and beautiful than dissonant relationships which sound unpleasant, discordant, or rough. The study of harmony involves chords and their construction and chord progressions and the principles of connection that govern them. Counterpoint, which refers to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhythm
Rhythm (from Greek , ''rhythmos'', "any regular recurring motion, symmetry") generally means a " movement marked by the regulated succession of strong and weak elements, or of opposite or different conditions". This general meaning of regular recurrence or pattern in time can apply to a wide variety of cyclical natural phenomena having a periodicity or frequency of anything from microseconds to several seconds (as with the riff in a rock music song); to several minutes or hours, or, at the most extreme, even over many years. Rhythm is related to and distinguished from pulse, meter, and beats: In the performance arts, rhythm is the timing of events on a human scale; of musical sounds and silences that occur over time, of the steps of a dance, or the meter of spoken language and poetry. In some performing arts, such as hip hop music, the rhythmic delivery of the lyrics is one of the most important elements of the style. Rhythm may also refer to visual presentation, as "timed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonality
Tonality is the arrangement of pitches and/or chords of a musical work in a hierarchy of perceived relations, stabilities, attractions and directionality. In this hierarchy, the single pitch or triadic chord with the greatest stability is called the tonic. The root of the tonic chord forms the name given to the key, so in the key of C major, the note C is both the tonic of the scale and the root of the tonic chord (which is C–E–G). Simple folk music songs often start and end with the tonic note. The most common use of the term "is to designate the arrangement of musical phenomena around a referential tonic in European music from about 1600 to about 1910". Contemporary classical music from 1910 to the 2000s may practice or avoid any sort of tonality—but harmony in almost all Western popular music remains tonal. Harmony in jazz includes many but not all tonal characteristics of the European common practice period, usually known as "classical music". "All harmonic idi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitch Class
In music, a pitch class (p.c. or pc) is a set of all pitches that are a whole number of octaves apart; for example, the pitch class C consists of the Cs in all octaves. "The pitch class C stands for all possible Cs, in whatever octave position." Important to musical set theory, a pitch class is "all pitches related to each other by octave, enharmonic equivalence, or both." Thus, using scientific pitch notation, the pitch class "C" is the set : = . Although there is no formal upper or lower limit to this sequence, only a few of these pitches are audible to humans. Pitch class is important because human pitch-perception is periodic: pitches belonging to the same pitch class are perceived as having a similar quality or color, a property called " octave equivalence". Psychologists refer to the quality of a pitch as its "chroma". A ''chroma'' is an attribute of pitches (as opposed to ''tone height''), just like hue is an attribute of color. A ''pitch class'' is a set of all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Envelope Detector
An envelope detector (sometimes called a peak detector) is an electronic circuit that takes a (relatively) high-frequency amplitude modulated signal as input and provides an output, which is the demodulated ''envelope'' of the original signal. Circuit operation The capacitor in the circuit above stores charge on the rising edge and releases it slowly through the resistor when the input signal amplitude falls. The diode in series rectifies the incoming signal, allowing current flow only when the positive input terminal is at a higher potential than the negative input terminal. General considerations Most practical envelope detectors use either half-wave or full-wave rectification of the signal to convert the AC audio input into a pulsed DC signal. Filtering is then used to smooth the final result. This filtering is rarely perfect and some "ripple" is likely to remain on the envelope follower output, particularly for low frequency inputs such as notes from a bass instrume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pitch Detection Algorithm
Pitch may refer to: Acoustic frequency * Pitch (music), the perceived frequency of sound including "definite pitch" and "indefinite pitch" ** Absolute pitch or "perfect pitch" ** Pitch class, a set of all pitches that are a whole number of octaves apart ** Relative pitch, the ability to identify a given musical interval between two notes * Pitch accent, a form of accentuation in speech Business * Sales pitch, a line of talk that attempts to persuade someone or something ** Pitch (filmmaking), a proposal for a film ** Elevator pitch, a very short sales presentation, allegedly short enough to be made during an elevator ride Measurement Movement about the transverse axis * Pitch angle (or pitch rotation), one of the angular degrees of freedom of any stiff body (for example a vehicle), describing rotation about the side-to-side axis ** Pitch (aviation), one of the aircraft principal axes of rotation (nose-up or nose-down angle measured from horizontal axis) ** Pitch (ship motio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feature Extraction
In machine learning, pattern recognition, and image processing, feature extraction starts from an initial set of measured data and builds derived values (features) intended to be informative and non-redundant, facilitating the subsequent learning and generalization steps, and in some cases leading to better human interpretations. Feature extraction is related to dimensionality reduction. When the input data to an algorithm is too large to be processed and it is suspected to be redundant (e.g. the same measurement in both feet and meters, or the repetitiveness of images presented as pixels), then it can be transformed into a reduced set of features (also named a feature vector). Determining a subset of the initial features is called feature selection. The selected features are expected to contain the relevant information from the input data, so that the desired task can be performed by using this reduced representation instead of the complete initial data. General Feature extracti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Music
Computer music is the application of computing technology in music composition, to help human composers create new music or to have computers independently create music, such as with algorithmic composition programs. It includes the theory and application of new and existing computer software technologies and basic aspects of music, such as sound synthesis, digital signal processing, sound design, sonic diffusion, acoustics, electrical engineering and psychoacoustics. The field of computer music can trace its roots back to the origins of electronic music, and the first experiments and innovations with electronic instruments at the turn of the 20th century. History Much of the work on computer music has drawn on the relationship between music and mathematics, a relationship which has been noted since the Ancient Greeks described the " harmony of the spheres". Musical melodies were first generated by the computer originally named the CSIR Mark 1 (later renamed CSIRAC) in Aus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Musicology
Musicology (from Greek μουσική ''mousikē'' 'music' and -λογια ''-logia'', 'domain of study') is the scholarly analysis and research-based study of music. Musicology departments traditionally belong to the humanities, although some music research is scientific in focus (psychological, sociological, acoustical, neurological, computational). Some geographers and anthropologists have an interest in musicology so the social sciences also have an academic interest. A scholar who participates in musical research is a musicologist. Musicology traditionally is divided in three main branches: historical musicology, systematic musicology and ethnomusicology. Historical musicologists mostly study the history of the western classical music tradition, though the study of music history need not be limited to that. Ethnomusicologists draw from anthropology (particularly field research) to understand how and why people make music. Systematic musicology includes music theory, aes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory Scene Analysis
In perception and psychophysics, auditory scene analysis (ASA) is a proposed model for the basis of auditory perception. This is understood as the process by which the human auditory system organizes sound into perceptually meaningful elements. The term was coined by psychologist Albert Bregman. The related concept in machine perception is computational auditory scene analysis (CASA), which is closely related to source separation and blind signal separation. The three key aspects of Bregman's ASA model are: segmentation, integration, and segregation. Background Sound reaches the ear and the eardrum vibrates as a whole. This signal has to be analyzed (in some way). Bregman's ASA model proposes that sounds will either be heard as "integrated" (heard as a whole – much like harmony in music), or "segregated" into individual components (which leads to counterpoint). For example, a bell can be heard as a 'single' sound (integrated), or some people are able to hear the individual ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
