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distortion

Variation of magnification across the field of view of a lens. It can be either pincushion or barrel distortion.

distortion

distortion   Quick reference

A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018

... Variation of magnification across the field of view of a lens. It can be either pincushion or barrel distortion...

distortion

distortion   Quick reference

A Dictionary of Electronics and Electrical Engineering (5 ed.)

Reference type:
Subject Reference
Current Version:
2018
Subject:
Science and technology, Engineering and Technology
Length:
462 words
Illustration(s):
1

...distortion of a complex waveform arises from intermodulation within the waveform. • Nonlinear distortion is produced in a system when the instantaneous transmission properties depend on the magnitude of the input. Amplitude, harmonic, and intermodulation distortion are all results of nonlinear distortion. • Phase distortion occurs when the phase change introduced is not a linear function of frequency. Optical distortion of an image is seen in electronic systems due to errors in the electron-lens focusing systems. Optical distortion • ...

distortion

distortion   Quick reference

A Dictionary of Physics (8 ed.)

Reference type:
Subject Reference
Current Version:
2019
Subject:
Science and technology, Physics
Length:
32 words

...distortion The extent to which a system fails to reproduce the characteristics of its input in its output. It is most commonly applied to electronic amplifiers and to optical systems. See aberration ....

Distortion

Distortion   Reference library

The Oxford Dictionary of Byzantium

Reference type:
Subject Reference
Current Version:
2005
Subject:
History, Early history (500 CE to 1500)
Length:
140 words

... , the alteration in shape or proportion in an image, frequently employed to convey values on a hierarchical scale , the expression of emotion —less often used than in the medieval West—or for purposes of caricature . Despite antique theoretical systems designed to avoid distortion, which were transmitted by Proklos , the absence of coherent perspective often resulted in what, to the modern eye, appear to be deformations of space and proportion. Some distortions, however, are evidently attempts by the artist to compensate for the spectator's...

distortion

distortion   Quick reference

A Dictionary of Media and Communication (3 ed.)

Reference type:
Subject Reference
Current Version:
2020
Subject:
Media studies
Length:
136 words

... 1. Misrepresentation or inaccuracy in the ostensibly objective reporting or representation of something: see also bias . 2. In relation to perception and memory , unconscious modifications to the source material: see also addition ; assimilation ; deletion ; levelling and sharpening ; substitution ; transposition ; unconscious bias . 3. In psychoanalytic theory , a defence mechanism that disguises dream content : see also condensation ; displacement . 4. In relation to lenses (both in physiology and optical devices),...

distortion

distortion (in hearing aids)   Quick reference

A Dictionary of Audiology (2 ed.)

Reference type:
Subject Reference
Current Version:
2016
Subject:
Medicine and health
Length:
197 words

...distortion ( in hearing aids ) The undesired alteration of the signal entering a hearing aid. Types of distortion encountered in hearing aids include total harmonic distortion (THD), intermodulation distortion (IMD) and transient distortion. Transient distortion occurs when a hearing aid is not able to reproduce the initial attack or sudden decay of an impulse sound. IMD occurs when a non-linear sound is introduced into a complex signal. THD is most frequently measured. IMD is much more destructive to intelligibility than THD but is generally much less easy...

hysteresis distortion

hysteresis distortion   Quick reference

A Dictionary of Electronics and Electrical Engineering (5 ed.)

Reference type:
Subject Reference
Current Version:
2018

...distortion Distortion introduced by nonlinear hysteresis in one or more elements of a system. ...

pincushion distortion

pincushion distortion   Quick reference

A Dictionary of Computer Science (7 ed.)

Reference type:
Subject Reference
Current Version:
2016

...distortion A distortion that makes a displayed image appear to bulge inward on all four...

negative distortion

negative distortion   Quick reference

A Dictionary of Forensic Science

Reference type:
Subject Reference
Current Version:
2013
Subject:
Science and technology, Law
Length:
51 words

...distortion ( barrel distortion ) In microscopy, an optical aberration that arises from the optics in which the centre of the sample field of view experiences greater magnification relative to the edges; thus the term ‘barrel distortion’. This contrasts with a positive or pincushion distortion in which the opposite...

distortion energy

distortion energy   Quick reference

A Dictionary of Mechanical Engineering (2 ed.)

Reference type:
Subject Reference
Current Version:
2019

...distortion energy (Unit J) The elastic strain energy associated with change of shape of a...

angular distortion

angular distortion   Quick reference

A Dictionary of Mechanical Engineering (2 ed.)

Reference type:
Subject Reference
Current Version:
2019

...angular distortion (Unit ° or rad) Longitudinal warping in the torsion of a non-circular...

harmonic distortion

harmonic distortion   Quick reference

A Dictionary of Electronics and Electrical Engineering (5 ed.)

Reference type:
Subject Reference
Current Version:
2018
Subject:
Science and technology, Engineering and Technology
Length:
156 words
Illustration(s):
2

...distortion The distortion of a waveform caused by the nonlinear effect of a system or component that creates harmonic frequencies that would not otherwise be present at the output. The extent to which a particular harmonic component distorts a signal is given by the ratio of its amplitude A n to the amplitude of the fundamental component A f , expressed as a percentage: The total harmonic distortion ( THD ) is the square root of the sum of the squares of all the individual harmonic distortions: where the individual harmonic distortion D n is...

pincushion distortion

pincushion distortion   Quick reference

A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018

...distortion An optical defect in which the magnification of a lens decreases with distance from the optical axis, giving the image of a square object with concave sides, like a pincushion....

perceptual distortion

perceptual distortion   Quick reference

A Dictionary of Organizational Behaviour

Reference type:
Subject Reference
Current Version:
2019
Subject:
Social sciences, Business and Management
Length:
154 words

...distortion Any of the inevitable distortions in our perceptions that occur when we attend to, organize and interpret sensory data. These include distortions such as selective perception , habituation , attribution theory, halo effect , and stereotypes . Perceptual distortions occur because we are unable to attend to all sensory data and we need to manage and make sense of the wealth of data. During this process we rely on data processing rules we have established by drawing on previous experience and attitudes prevalent in society that inform...

barrel distortion

barrel distortion   Quick reference

A Dictionary of Astronomy (3 ed.)

Reference type:
Subject Reference
Current Version:
2018

...distortion An optical defect in which the magnification of a lens is slightly greater close to its optical axis than at the edges. The image of a square object then has convex sides, hence the name....

segregation distortion

segregation distortion   Quick reference

A Dictionary of Genetics (8 ed.)

Reference type:
Subject Reference
Current Version:
2014
Subject:
Science and technology, Life Sciences
Length:
68 words

...distortion a distortion of expected Mendelian ratios in a cross due to dysfunction or lethality in gametes bearing certain alleles. This form of meiotic drive ( q.v. ) is represented in Drosophila melanogaster by the segregation distorter ( SD ) mutation on chromosome 2. SD/sd + heterozygous males produce both SD and sd + spermatozoa, but only those carrying SD are functional. SD cannot achieve fixation, however, because it is lethal when...

Meiotic Distortion

Meiotic Distortion   Reference library

Encyclopedia of Evolution

Reference type:
Subject Reference
Current Version:
2005
Subject:
Science and technology, Life Sciences, Social sciences, Anthropology
Length:
3,891 words
Illustration(s):
1

...the strength of male drive. In one exceptional population, a spontaneous secondary translocation of part of an SD chromosome to the tip of the X chromosome allowed the sex-ratio distortion to actually be reversed, providing a startling example of the flexibility of evolutionary response to sex-ratio distortion. Terrence W. Lyttle Evolutionary Implications of Meiotic Distortion Recently, there has been considerable debate as as to whether complementary systems of sex chromosome drive fixed in different species can provide an explanation for Haldane's Rule....

segregation ratio distortion

segregation ratio distortion   Quick reference

A Dictionary of Genetics (8 ed.)

Reference type:
Subject Reference
Current Version:
2014
Subject:
Science and technology, Life Sciences
Length:
52 words

...ratio distortion the distortion of the 1:1 segregation ratio produced by a heterozygote. Such distortions may arise because of abnormalities of meiosis that result in an Aa individual’s producing unequal numbers of A - and a -bearing gametes, or it may arise from A - and a -bearing gametes being unequally effective in producing...

wide‐angle distortion

wide‐angle distortion   Reference library

Roger W. Hicks

The Oxford Companion to the Photograph

Reference type:
Subject Reference
Current Version:
2006
Subject:
Art & Architecture
Length:
123 words

...distortion . True wide‐angle distortion describes the way in which three‐dimensional objects near the edges of the field of view appear ‘stretched’ out of shape because of the angle of view of the lens: a round ball is distorted into an ellipse, and a human head can look quite unpleasant. It is not so much a defect as an inherent property of extreme wide‐angle lenses: it cannot be ‘designed out’ and has been used to powerful creative effect, most notably in the nudes of Bill Brandt . It should not be confused with another kind of distortion sometimes...

distortion product otoacoustic emission

distortion product otoacoustic emission   Quick reference

Phil Gomersall

A Dictionary of Audiology (2 ed.)

Reference type:
Subject Reference
Current Version:
2016
Subject:
Medicine and health
Length:
241 words

...placed in the ear canal to deliver the stimulus tones incorporates a sensitive, calibrated microphone in order to record the distortion products, along with signal processing to assist in the identification of their presence. The generation of cochlear distortion products relies on non-linear activity of the outer hair cells of the cochlea. The specific frequency of the distortion products generated depends upon the population of outer hair cells stimulated, which in turn depends upon the frequency of the stimulus tones. This means that a loss in hearing...

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