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Visual artifacts (also artefacts) are anomalies apparent during visual representation as in digital graphics and other forms of
image An image is a visual representation of something. It can be two-dimensional, three-dimensional, or somehow otherwise feed into the visual system to convey information. An image can be an artifact, such as a photograph or other two-dimensiona ...
ry, especially
photography Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed i ...
and microscopy.


In digital graphics

* Image quality factors, different types of visual artifacts *
Compression artifact A compression artifact (or artefact) is a noticeable distortion of media (including images, audio, and video) caused by the application of lossy compression. Lossy data compression involves discarding some of the media's data so that it b ...
s * Digital artifacts, visual artifacts resulting from digital image processing * Noise *
Screen-door effect The screen-door effect (SDE) is a visual artifact of displays, where the fine lines separating pixels (or subpixels) become visible in the displayed image. This can be seen in digital projector images and regular displays under magnification or ...
, also known as fixed-pattern noise (FPN), a visual artifact of digital projection technology * Ghosting (television) * Screen burn-in *
Distortion In signal processing, distortion is the alteration of the original shape (or other characteristic) of a signal. In communications and electronics it means the alteration of the waveform of an information-bearing signal, such as an audio sig ...
*
Silk screen effect The silk screen effect (SSE) is a visual phenomenon seen in rear-projection televisions. SSE is described by viewers as seeing the texture of the television screen in front of the image. SSE may be found on all rear-projection televisions includin ...
* Rainbow effect *
Screen tearing Screen tearing is a visual artifact in video display where a display device shows information from multiple frames in a single screen draw. The artifact occurs when the video feed to the device is not synchronized with the display's refresh ra ...
*
Moiré pattern In mathematics, physics, and art, moiré patterns ( , , ) or moiré fringes are large-scale interference patterns that can be produced when an opaque ruled pattern with transparent gaps is overlaid on another similar pattern. For the moiré ...
*
Color banding Colour banding is a subtle form of posterization in digital images, caused by the colour of each pixel being rounded to the nearest of the digital colour levels. While posterization is often done for artistic effect, colour banding is an unde ...


In video entertainment

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 bug A software bug is an error, flaw or fault in the design, development, or operation of computer software that causes it to produce an incorrect or unexpected result, or to behave in unintended ways. The process of finding and correcting bugs ...
s in the application or operating system. The differing cases of visual artifacting can also differ between scheduled task(s).


In photography

These effects can occur in both analog and
digital photography Digital photography uses cameras containing arrays of electronic photodetectors interfaced to an analog-to-digital converter (ADC) to produce images focused by a lens, as opposed to an exposure on photographic film. The digitized image is ...
. *
Chromatic aberration In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wa ...
due to
optical dispersion In optics, and by analogy other branches of physics dealing with wave propagation, dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency; sometimes the term chromatic dispersion is used for specificity to o ...
through a
lens A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
, leading to color fringes at high-contrast boundaries in a photograph ** Purple fringing *
Motion blur Motion blur is the apparent streaking of moving objects in a photograph or a sequence of frames, such as a film or animation. It results when the image being recorded changes during the recording of a single exposure, due to rapid movement or l ...
* Near-camera reflection, visual artifacts caused by the
backscatter In physics, backscatter (or backscattering) is the reflection of waves, particles, or signals back to the direction from which they came. It is usually a diffuse reflection due to scattering, as opposed to specular reflection as from a mirror, ...
of light by unfocused particles


In microscopy

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 Microscopy is the technical field of using microscopes to view objects and areas of objects that cannot be seen with the naked eye (objects that are not within the resolution range of the normal eye). There are three well-known branches of micr ...
, artifacts may be produced by air bubbles trapped under the
slide Slide or Slides may refer to: Places * Slide, California, former name of Fortuna, California Arts, entertainment, and media Music Albums * ''Slide'' (Lisa Germano album), 1998 * ''Slide'' (George Clanton album), 2018 *''Slide'', by Patrick Glees ...
's cover slip. 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 In cell biology, cell fractionation is the process used to separate cellular components while preserving individual functions of each component. This is a method that was originally used to demonstrate the cellular location of various biochemical ...
may be used to overcome the problems of artifacts. A ''crush artifact'' is an artificial elongation and distortion seen in
histopathology Histopathology (compound of three Greek words: ''histos'' "tissue", πάθος ''pathos'' "suffering", and -λογία ''-logia'' "study of") refers to the microscopic examination of tissue in order to study the manifestations of disease. Spec ...
and
cytopathology Cytopathology (from Greek , ''kytos'', "a hollow"; , ''pathos'', "fate, harm"; and , ''-logia'') is a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by George Nicolas Papanicolaou in 1 ...
studies, presumably because of iatrogenic compression of tissues. Distortion can be caused by the slightest compression of tissue and can provide difficulties in diagnosis. It may cause chromatin to be squeezed out of nuclei. 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 Hematoxylin and eosin stain ( or haematoxylin and eosin stain or hematoxylin-eosin stain; often abbreviated as H&E stain or HE stain) is one of the principal tissue stains used in histology. It is the most widely used stain in medical diagn ...
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.
- 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 A resection margin or surgical margin is the margin of apparently non-tumorous tissue around a tumor that has been surgically removed, called " resected", in surgical oncology. The resection is an attempt to remove a cancer tumor so that no portio ...
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 artifact, seen as a tail-like extension of nuclear material.


In radiography

In
projectional radiography Projectional radiography, also known as conventional radiography, is a form of radiography and medical imaging that produces two-dimensional images by x-ray radiation. The image acquisition is generally performed by radiographers, and the images ...
, visual artifacts that can constitute disease mimics include jewelry, clothes and
skin fold Skin folds or skinfolds are areas of skin that are naturally folded. Many skin folds are distinct, heritable anatomical features, and may be used for identification of animal species, while others are non-specific and may be produced either by ind ...
s.Page 46
in:
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 A chest radiograph, called a chest X-ray (CXR), or chest film, is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in med ...


In magnetic resonance imaging

In
Magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wav ...
, artifacts can be classified as patient-related, signal processing-dependent or hardware (machine)-related.(CC-BY 4.0)
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References

{{Reflist Computer graphic artifacts Visual artifacts