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-dimensio ...

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 emplo ...

and

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 ...

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 beco ...

s * Digital artifacts, visual artifacts resulting from digital image processing *

Noise Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference aris ...

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 o ...

, also known as fixed-pattern noise (FPN), a visual artifact of digital projection technology * Ghosting (television) *

Screen burn-in Screen burn-in, image burn-in, or ghost image, is a permanent discoloration of areas on an electronic display such as a cathode ray tube (CRT) in an old computer monitor or television set. It is caused by cumulative non-uniform use of the s ...

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 signa ...

* Silk screen effect * 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 r ...

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

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 A graphics card (also called a video card, display card, graphics adapter, VGA card/VGA, video adapter, display adapter, or mistakenly GPU) is an expansion card which generates a feed of output images to a display device, such as a computer m ...

(graphics card) drivers. * Drivers that have values that the graphics card is not suited with. *

Overclocking In computing, overclocking is the practice of increasing the clock rate of a computer to exceed that certified by the manufacturer. Commonly, operating voltage is also increased to maintain a component's operational stability at accelerated sp ...

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 i ...

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 ...

. *

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 w ...

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 In photography (particularly digital photography), purple fringing (sometimes called PF) is the term for an unfocused purple or magenta "ghost" image on a photograph. This optical aberration is generally most visible as a coloring and lightening ...

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 lo ...

* 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, a ...

of light by unfocused particles

In microscopy

Anther of thale cress (Arabidopsis thaliana), an artefact

, 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's cover slip. In

electron microscopy An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a hi ...

, distortions may be produced in the drying out of the specimen.

Staining Staining is a technique used to enhance contrast in samples, generally at the microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissues), in cytology (microscopic study of cells), and in th ...

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 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. Sp ...

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 ...

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 diag ...

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 A microtome (from the Greek ''mikros'', meaning "small", and ''temnein'', meaning "to cut") is a cutting tool used to produce extremely thin slices of material known as ''sections''. Important in science, microtomes are used in microscopy, allo ...

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 artifact, seen as a tail-like extension of nuclear material.

In radiography

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 a ...

, visual artifacts that can constitute disease mimics include jewelry, clothes and skin folds.Page 46
in: File:Skin folds close to a hip fracture (with arrows).jpg, A

hip fracture A hip fracture is a break that occurs in the upper part of the femur (thigh bone). Symptoms may include pain around the hip, particularly with movement, and shortening of the leg. Usually the person cannot walk. They most often occur as a res ...

(black arrow) next to a skin fold (white arrow). File:Bed sheets artifact on lateral chest radiograph.jpg,

Bed sheets A bed sheet is a rectangular piece of cloth used either singly or in a pair as bedding, which is larger in length and width than a mattress, and which is placed immediately above a mattress or bed, but below blankets and other bedding (such as ...

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

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 wave ...

, artifacts can be classified as patient-related, signal processing-dependent or hardware (machine)-related.(CC-BY 4.0)
/ref>

References

{{Reflist Computer graphic artifacts Visual artifacts