Visual artifact#In microscopy

File:Retinography.jpg. The gray spot in the center is a shadow artifact.]]

• Image quality factors, different types of visual artifacts
• Compression artifacts
• Digital artifacts, visual artifacts resulting from digital image processing
• Noise
• Screen-door effect, also known as fixed-pattern noise (FPN), a visual artifact of digital projection technology
• Ghosting (television)
• Screen burn-in
• Distortion
• Silk screen effect
• Rainbow effect
• Screen tearing
• Moiré pattern
• Color banding

Many people who use their computers as a hobby experience artifacting due to a hardware or software malfunction. The cases can differ but the usual causes are:

• Temperature issues, such as failure of cooling fan.
• Unsuited video card (graphics card) drivers.
• Drivers that have values that the graphics card is not suited with.
• Overclocking beyond the capabilities of the particular video card.
• Software bugs in the application or operating system.

The differing cases of visual artifacting can also differ between scheduled task(s).

File:Experiment_Rain_Orbs_1.jpg

These effects can occur in both analog and digital photography.

• Chromatic aberration due to optical dispersion through a lens, leading to color fringes at high-contrast boundaries in a photograph
• Purple fringing
• Motion blur
• Near-camera reflection, visual artifacts caused by the backscatter of light by unfocused particles

File:Anther of thale cress (Arabidopsis thaliana), an artefact.jpg anther (part of stamen). The picture shows among other things a nice red flowing collar-like structure just below the anther. However, an intact thale cress stamen does not have such collar, this is a fixation artifact: the stamen has been cut below the picture frame, and epidermis (upper layer of cells) of stamen stalk has peeled off, forming a non-characteristic structure. Photo: Heiti Paves from Tallinn University of Technology.]]

In microscopy, an artifact is an apparent structural detail that is caused by the processing of the specimen and is thus not a legitimate feature of the specimen. In light microscopy, artifacts may be produced by air bubbles trapped under the slide's cover slip.{{cite book |last1=Kent |first1=Michael |title=Advanced Biology |date=2000 |publisher=Oxford University Press |location=Oxford |isbn=0199141959 |page=64 |edition=Repr.}}

In electron microscopy, distortions may be produced in the drying out of the specimen. Staining can cause the appearance of solid chemical deposits that may be seen as structures inside the cell. Different techniques including freeze-fracturing and cell fractionation may be used to overcome the problems of artifacts.

A crush artifact is an artificial elongation and distortion seen in histopathology and cytopathology studies, presumably because of iatrogenic compression of tissues. Distortion can be caused by the slightest compression of tissue and can provide difficulties in diagnosis.{{cite journal |last1=Chatterjee |first1=S. |title=Artefacts in histopathology |journal= Journal of Oral and Maxillofacial Pathology|date=September 2014 |volume=18 |issue=Suppl 1 |pages=S111-6 |doi=10.4103/0973-029X.141346 |pmid=25364159|pmc=4211218 |doi-access=free }}{{cite journal |vauthors=Komanduri S, Swanson G, Keefer L, Jakate S |title=Use of a new jumbo forceps improves tissue acquisition of Barrett's esophagus surveillance biopsies |journal= Gastrointestinal Endoscopy|volume=70 |issue=6 |pages=1072–8.e1 |date=December 2009 |pmid=19595312 |doi=10.1016/j.gie.2009.04.009 }} It may cause chromatin to be squeezed out of nuclei.{{cite journal|last1=Chatterjee|first1=Shailja|title=Artefacts in histopathology|journal=Journal of Oral and Maxillofacial Pathology|volume=18|issue=4|year=2014|pages=S111–S116|issn=0973-029X|doi=10.4103/0973-029X.141346|pmid=25364159|pmc=4211218 |doi-access=free }} Inflammatory and tumor cells are most susceptible to crush artifacts.

File:Cellulose contamination in H&E and polarized light.jpg|Cellulose contamination, in H&E stain and polarized light

File:Histopathology of cardiac muscle with contamination from thyroid tissue.jpg|Cardiac muscle (bottom) with contamination from thyroid tissue (center)

File:Crush artifact from forceps.jpg|Crush artifact from compression by forceps on the tissue sample

File:Skin with folds and crush artifact by needle.jpg|Folding artifacts (white arrows) and a crush artifact (black arrow, with cytoplasmic hypereosinophilia and nuclear pleomorphism) from a needle

File:Microscopy of liver parenchyma with tearing artifacts.jpg|Tearing artifacts, such as can be caused by:
- Microtomy with a nick or blemish in the knife edge.{{cite journal|last1=Taqi|first1=SyedAhmed|last2=Sami|first2=SyedAbdus|last3=Sami|first3=LateefBegum|last4=Zaki|first4=SyedAhmed|title=A review of artifacts in histopathology|journal=Journal of Oral and Maxillofacial Pathology|volume=22|issue=2|year=2018|pages=279|issn=0973-029X|doi=10.4103/jomfp.JOMFP_125_15|pmid=30158787|pmc=6097380 |doi-access=free }}
- Traction of the sections.
- Too much or too little alcohol dehydration.
- Sectioning calcified parts, which can be decalcified or removed.

File:Formalin pigment artifacts.jpg|Formalin pigment artifacts

File:Air bubble entrapment artifact.png|Air bubble entrapment artifact in a shoulder joint biopsy

File:Staining artifacts by residual wax.jpg|Staining artifacts by residual wax, resulting in pale areas where cellular structures are not discernible

File:Histopathology of radically excised basal-cell carcinoma with separation artifact (horizontal layout).jpg|A separation artifact in top image makes the tumor look incompletely excised, but the next microtomy level (bottom image) shows a surgical margin of connective tissue.

File:Micrograph of stacked cells.jpg|Stacking of cells on top of each other gives a dark look, and in this breast tissue it may mimic microcalcifications.

File:Pap smear of a monocyte with nuclear smearing artifact.jpg|Pap stained smear of a monocyte with nuclear smearing or smudging artifact, seen as a tail-like extension of nuclear material

File:Histopathology of small cell carcinoma - nuclear smudging.png|Small cell carcinoma is a cancer where the presence of smudging is a clue to the diagnosis.Image by Mikael Häggström, MD. Source for findings: {{cite web|url=https://www.pathologyoutlines.com/topic/lungtumorsmallcell.html|title=Lung - Small cell carcinoma|website=Pathology Outlines|author=Caroline I.M. Underwood, M.D., Carolyn Glass, M.D., Ph.D.}} Last author update: 20 September 2022

In projectional radiography, visual artifacts that can constitute disease mimics include jewelry, clothes and skin folds.[https://books.google.com/books?id=NItlwYj0aLcC&pg=PA46 Page 46] in: {{cite book|title=Pocket Tutor Chest X-Ray Interpretation|author=Michael Darby, Nicholas Maskell, Anthony Edey, Ladli Chandratreya|publisher=JP Medical Ltd|year=2012|isbn=9781907816062}}

File:Skin folds close to a hip fracture (with arrows).jpg|A hip fracture (black arrow) next to a skin fold (white arrow)

File:Bed sheets artifact on lateral chest radiograph.jpg|Bed sheets looking like lung opacities on a chest radiograph

{{Main|MRI artifact|Ghosting (medical imaging)}}

In Magnetic resonance imaging, artifacts can be classified as patient-related, signal processing-dependent or hardware (machine)-related.{{cite journal|last1=Erasmus|first1=L.J.|last2=Hurter|first2=D.|last3=Naude|first3=M.|last4=Kritzinger|first4=H.G.|last5=Acho|first5=S.|title=A short overview of MRI artifacts|journal=South African Journal of Radiology|volume=8|issue=2|pages=13|year=2004|issn=2078-6778|doi=10.4102/sajr.v8i2.127|doi-access=free}} [https://creativecommons.org/licenses/by/4.0/ (CC-BY 4.0)]

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Category:Computer graphic artifacts

Category:Visual artifacts