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single reflection (while an echo can be reflected several times before reaching the transducer); depth of an object relates directly to the amount of time for an echo to reach the transducer (while an echo may reflect several times, delaying the time for the echo return to the transducer); speed of ultrasound in human tissue is constant, echoes travel in a straight path. and acoustic energy of an echo is uniformly attenuated. When these assumptions are not maintained, artifacts occur.
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In ultrasound imaging, several assumptions are made from the computer system to interpret the returning echoes. These are: echoes originate only from the main ultrasound beam (while there are side lobes and grating lobes apart from the main ultrasound beam); echoes returns to transducer after a
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monitoring, artifacts are anomalous (interfering) signals that originate from some source other than the electrophysiological structure being studied. These artifact signals may stem from, but are not limited to: light sources; monitoring equipment issues; utility frequency (50 Hz and
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is approximately equal to twice the percentage of citizens making more than $ 50,000 annually; if 60% of citizens make more than $ 50,000 annually, this would predict that the approval rating will be 120%. This prediction is a statistical artifact, since it is spurious to use the
151:, an artifact is a spurious finding, such as one based on either a faulty choice of variables or an over-extension of the computed relationship. Such an artifact may be called a
296:, and many other effects. All those echoes must be filtered in order to obtain the position, velocity and type of the real targets that may include aircraft, and weather.
203:(MRI). These artifacts may be caused by a variety of phenomena such as the underlying physics of the energy-tissue interaction as between ultrasound and air,
89:, statistical artifacts are apparent effects that are introduced inadvertently during analysis of data rather than by the process being studied.
211:'s inability to represent the anatomy. Physicians typically learn to recognize some of these artifacts to avoid mistaking them for actual
252:- signal. Offending artifacts may obscure, distort, or completely misrepresent the true underlying electrophysiological signal sought.
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when the percentage of citizens making over $ 50,000 is so high, and gross error to predict an approval rating greater than 100%.
308:, in sound and music production, sonic material that is accidental or unwanted, resulting from the editing of another sound.
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in the perception or representation of any information introduced by the involved equipment or technique(s).
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Feldman, Myra K.; Katyal, Sanjeev; Blackwood, Margaret S. (July 2009). "US Artifacts".
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60 Hz); or undesired electrophysiological signals such as
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are sometimes introduced during the processing of samples into
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are anomalies introduced into digital signals as a result of
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John Scott; Gordon
Marshall (2009), "statistical artefact",
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Any error in the perception or representation of information
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339:"Oxford Languages | the Home of Language Data"
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359:, definitions 4, 5, and 6. Accessed 2010.05.20.
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109:digital signal processing
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18:Artifact (observational)
274:radar signal processing
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280:), multipath returns,
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294:anomalous propagation
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177:Further information:
51:of an optical system.
47:of light through the
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415:10.1148/rg.294085199
318:Compression artifact
229:electrophysiological
153:statistical artifact
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37:Diffraction spikes
456:Optical illusions
236:presenting on an
105:digital artifacts
61:signal processing
16:(Redirected from
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189:ultrasound
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79:Statistics
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213:pathology
209:algorithm
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69:artefact
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451:Error
256:Radar
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