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
References in periodicals archive ?
Vertical and horizontal edges of block in each macroblock (MB) of a frame are filtered for suppression of blocking artifacts. Luminance and chrominance components of video are separately filtered by H.264/AVC deblocking filter.
Evaluation of H.264/AVC deblocking filter for suppression of blocking artifacts is carried out using joint reference model software version 10.2 (Karsten, 2010).
It has been observed that H.264/AVC deblocking filter can do substantial suppression of blocking artifacts. However, granular like noise appears and appearance of this noise overrides the effectiveness of deblocking filter in high definition video sequences at lower bit rates.
The DF reduces blocking artifacts by smoothing samples on each side of the boundaries, where the block boundaries come from the PUs and TUs, rather than the inherent boundaries of the picture.
Therefore, the learned dictionary will have the blocking artifacts. It is necessary to remove atoms including blocking artifacts and obtain dictionary without non-blocking component for the image deblocking.
Taking into account the characteristics of blocking artifacts, we only need to consider and use the vertical and horizontal gradients in each dictionary atom.
If the residual threshold is too small, there are still some blocking artifacts in the images, as shown in Fig.
To improve the quality of edge and texture regions, the non-local similarity of video frame is used to construct the regularization item, and the regularization item is mixed into the joint CS reconstruction model to remove the blurring and blocking artifacts in edge and texture regions.
5 that the 13th frame containing medium complex motions in Foreman recovered by MCI has some blocking artifacts (highlighted in red circle).
Experimental results show that the proposed method is not only robust to motion vector estimated wrongly, but also can to reduce blocking artifacts by using overlapped block in comparison with existing popular compensation methods.
The block size in the video signal corresponds to 8 pixels times the scaling factor in both horizontal and vertical directions, therefore, the identification of vertical blocking artifacts ([V.sub.ver_blocking]) is accomplished in a similar fashion.
4-(c), the blocking artifact always happens because of the codec operation which can affect the judgment of HVS to the VQ.