Visual artifacts (also artefacts) are anomalies apparent during visual representation as in digital graphics and other forms of

image An image or picture is a visual representation. An image can be Two-dimensional space, two-dimensional, such as a drawing, painting, or photograph, or Three-dimensional space, three-dimensional, such as a carving or sculpture. Images may be di ...

ry, especially

photography Photography is the visual arts, art, application, and practice of creating 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 empl ...

and

microscopy Microscopy is the technical field of using microscopes to view subjects too small to 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 microscopy: optical mic ...

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 Image, images, Sound recording, audio, and video) caused by the application of lossy compression. Lossy data compression involves discarding some of the medi ...

s *

Digital artifact Digital artifact in information science, is any undesired or unintended alteration in data introduced in a digital process by an involved technique and/or technology. Digital artifact can be of any content types including text, audio, video, ...

s, visual artifacts resulting from digital image processing *

Noise Noise is sound, chiefly unwanted, unintentional, or harmful sound considered unpleasant, loud, or disruptive to mental or hearing faculties. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrat ...

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 effect can be seen in digital projector images and regular displays under magnifi ...

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

Ghosting (television) In television, a ghost is a replica of the transmitted image, offset in position, that is superimposed on top of the main image. It is often caused when a TV signal travels by two different paths to a receiving antenna, with a slight differen ...

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

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 signal ...

* 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 ra ...

Moiré pattern In mathematics, physics, and art, moiré patterns ( , , ) or moiré fringes are large-scale wave interference, interference patterns that can be produced when a partially opaque grating, ruled pattern with transparent gaps is overlaid on ano ...

* 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 accelerator, graphics adapter, VGA card/VGA, video adapter, display adapter, or colloquially GPU) is a computer expansion card that generates a feed of graphics output to a displa ...

(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 a design defect ( bug) in computer software. A computer program with many or serious bugs may be described as ''buggy''. The effects of a software bug range from minor (such as a misspelled word in the user interface) to sev ...

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, color aberration, color fringing, or purple fringing, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the ...

due to

optical dispersion Dispersion is the phenomenon in which the phase velocity of a wave depends on its frequency. Sometimes the term chromatic dispersion is used to refer to optics specifically, as opposed to wave propagation in general. A medium having this common ...

through a

lens A lens is a transmissive optical device that 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 of light by unfocused particles

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 subjects too small to 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 microscopy: optical, el ...

, 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 electrons as a source of illumination. It uses electron optics that are analogous to the glass lenses of an optical light microscope to control the electron beam, for instance focusing i ...

, 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 Microscope, microscopic level. Stains and dyes are frequently used in histology (microscopic study of biological tissue (biology), tissues), in cytology (microscopic ...

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 cell organelle, cellular components while preserving individual functions of each component. This is a method that was originally used to demonstrate the cellular location of vari ...

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: 'tissue', 'suffering', and '' -logia'' 'study of') is the microscopic examination of tissue in order to study the manifestations of disease. Specifically, in clinical medicine, histopatholog ...

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 level (bottom image) shows a

surgical margin A resection margin or surgical margin is the edge or "margin" of apparently non-tumorous tissue around a tumor that has been surgically removed, called "Resection (surgery), resected", in surgical oncology. The resection is an attempt to remove ...

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.

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 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 in ...

s.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), at the femoral neck or (rarely) the femoral head. Symptoms may include pain around the hip, particularly with movement, and shortening of the leg. Usually ...

(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, 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 medicine. L ...

In magnetic resonance imaging

Magnetic resonance imaging Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the anatomy and the physiological processes inside the body. MRI scanners use strong magnetic fields, magnetic field gradients, and ...

, 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