Artifact (error)
In natural science and signal processing, an artifact or artefact[1] is any error in the perception or representation of any information introduced by the involved equipment or technique(s).[2]
Computer science
In computer science, digital artifacts are anomalies introduced into digital signals as a result of digital signal processing.
Microscopy
In
Econometrics
In
Remote sensing
Medical imaging
In medical imaging, artifacts are misrepresentations of tissue structures produced by imaging techniques such as ultrasound, X-ray, CT scan, and magnetic resonance imaging (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, susceptibility artifacts, data acquisition errors (such as patient motion), or a reconstruction algorithm's inability to represent the anatomy. Physicians typically learn to recognize some of these artifacts to avoid mistaking them for actual pathology.
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 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.[4]
Medical electrophysiological monitoring
In medical
Radar
In radar signal processing, some echoes can be related to fixed objects (clutter), multipath returns, jamming, atmospheric effect (brightband or attenuation), anomalous propagation, 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.
See also
- Sonic artifact, in sound and music production, sonic material that is accidental or unwanted, resulting from the editing of another sound.
- Visual artifact, in imaging, any unwanted visual alteration introduced by the imaging equipment.
- Compression artifact, in computer graphics, distortion of media by the data compression.
References
- ^ "Oxford Languages | the Home of Language Data". Archived from the original on 1 July 2017.
- ^ See Dictionary.com, definitions 4, 5, and 6. Accessed 2010.05.20.
- ISBN 9780191726842
- PMID 19605664.