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artifact

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artifact

 [ahr´tĭ-fakt]
1. any artificial product; a structure or appearance that is not natural, but is due to manipulation.
2. distortion or fuzziness of an image caused by manipulation, such as during compression of a digital file.
film artifact artificial images on x-ray films due to storage, handling, or processing.
phantom artifact artificial images seen with conventional tomography.
standardization artifact an electrical stimulus of 1 mV deliberately introduced into the electrocardiogram so that pulse amplitudes on the tracing can be adjusted to 10 mm. The amplitudes of the P, QRS, and T intervals can be accurately evaluated only on an electrocardiogram thus standardized.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

ar·ti·fact

(ar'ti-fakt),
1. Anything, especially in a histologic specimen or a graphic record, which is caused by the technique used and does not reflect the original specimen or experiment.
2. A skin lesion produced or perpetuated by self-inflicted action, as in dermatitis artefacta.
Synonym(s): artefact
[L. ars, art, + facio, pp. factus, to make]
Farlex Partner Medical Dictionary © Farlex 2012

artifact

also

artefact

(är′tə-făkt′)
n.
1. A phenomenon or feature not originally present or expected and caused by an interfering external agent, action, or process, as an unwanted feature in a microscopic specimen after fixation, in a digitally reproduced image, or in a digital audio recording.
2. An inaccurate observation, effect, or result, especially one resulting from the technology used in scientific investigation or from experimental error: The apparent pattern in the data was an artifact of the collection method.

ar′ti·fac′tu·al (-făk′cho͝o-əl) adj.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.

artefact

(1) A structure not normally present, but produced by some external action; something artificial.
(2) The distortion of a substance or signal which interferes with or obscures the interpretation of a study, or a structure that is not representative of a specimen’s in vivo state, or which does not reflect the original sample, but rather is the result of an isolation procedure, its handling or other factors. Artefacts in electronic readout devices (e.g., EEG, EKG, and EMG) may be due to loose leads or electrical contacts.
 
Cardiology
An electrical impulse of noncardiac origin which is recorded as a vertical spike on an EKG or other ECG monitor (e.g., a pacemaker pulse); electrical signals from muscle contractions, or myopotentials, are called muscle artefacts.
 
Histology
Any change in tissue that occurs during tissue processing which may alter a tissue’s appearance and possibly the diagnosis.

Imaging
The artefact seen depends on the procedure. For example, in a barium enema, where zones of inconstant segmental contractions of the colon may be confused with organic constrictions or anatomic variations due to mucosal or intramural tumours, or a metal surgical clip that obscures an anatomical structure.
Segen's Medical Dictionary. © 2012 Farlex, Inc. All rights reserved.

artifact

Artefact A structure not normally present, but produced by some external action; something artificial; the distortion of a substance or signal, which interferes with or obscures the interpretation of a study, or a structure that is not representative of a specimen's in vivo state, or which does not reflect the original sample, but rather the result of an isolation procedure, its handling or other factors; artifacts in electronic readout devices–eg, EEG, EKG, and EMG, may be due to loose leads or electrical contacts Cardiac pacing An electrical impulse of noncardiac origin which is recorded as a vertical spike on an EKG or other ECG monitor–eg a pacemaker pulse; electrical signals from muscle contractions, or myopotentials, are called muscle artifacts Imaging The artifact seen depends on the procedure–eg, barium enema, where zones of inconstant segmental contractions of the colon may be confused with organic constrictions or anatomic variations, due to mucosal or intramural tumors, or a metal surgical clip that obscures an anatomical structure. See Beam-hardening artefact, Edge artefact, Mosaic artefact, Ring artefact.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.

ar·ti·fact

(ahr'ti-fakt)
1. Anything (especially in a histologic specimen or a graphic record) that is caused by the technique used or is not a natural occurrence but is merely incidental.
2. A skin lesion produced or perpetuated by self-inflicted action, such as scratching in dermatitis artefacta.
Synonym(s): artefact.
[L. ars, art, + facio, pp. factus, to make]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012

ar·ti·fact

, artefact (ahr'ti-fakt)
Anything, especially in a histologic specimen or a graphic record or x-ray, caused by the technique used that does not reflect the original specimen or experiment.
[L. ars, art, + facio, pp. factus, to make]
Medical Dictionary for the Dental Professions © Farlex 2012
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References in periodicals archive
We consider a sub-pixel algorithm to increase disparity precision on object surface by reducing quantization errors, which can be simply integrated with the existing disparity methods.
Topographic and quantization errors SOM NGN Stream Topographic error Quantization error Quantization error 1 5.57% 13.51 1.41 2 11.49% 36.86 3.39 3 12.58% 33.75 2.76 4 5.62% 9.76 4.16 5 55.85% 68.09 1.46 Source: authors Table 3.
The 25x25 topology and 5000 training epochs showed lower quantization error and better separation of the samples that allowed for the visualization of the groups in a topographic map.
As we know that when the input signal subjected to Gaussian distribution with mean 0, then the relation between autocorrelation function [R.sub.e](m) of quantization error and input signal can be expressed as follows:
In this method, the value of QEC is a constant, and it has the advantage of simplicity, but leads to large quantization error (QE).
In the first case, an M bits time shifter providing the desired time delay distribution needed to control a "continuous" beam steering (apart from quantization errors) is designed, for each radiating element.
[15]), the two-channel filter bank is susceptible to quantization error. This error can have a significant effect on the response of the filters and perfect reconstruction.
The quantization error is within 0.1% and is acceptable
Dither is a random noise added to a signal prior to it (re)quantization in order to control the statistical properties of the quantization error (Wannamaker et al., 2000).
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