computer graphics Computer graphics deals with generating images and art with the aid of computers. Computer graphics is a core technology in digital photography, film, video games, digital art, cell phone and computer displays, and many specialized applications. ...

, pixelation (also spelled pixellation in

British English British English is the set of Variety (linguistics), varieties of the English language native to the United Kingdom, especially Great Britain. More narrowly, it can refer specifically to the English language in England, or, more broadly, to ...

) is caused by displaying a

bitmap In computing, a bitmap (also called raster) graphic is an image formed from rows of different colored pixels. A GIF is an example of a graphics image file that uses a bitmap. As a noun, the term "bitmap" is very often used to refer to a partic ...

or a section of a bitmap at such a large size that individual

pixel In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a Raster graphics, raster image, or the smallest addressable element in a dot matrix display device. In most digital display devices, p ...

s, small single-colored square display elements that comprise the bitmap, are visible. Such an image is said to be pixelated ( pixellated in the UK). Early graphical applications such as

video game A video game or computer game is an electronic game that involves interaction with a user interface or input device (such as a joystick, game controller, controller, computer keyboard, keyboard, or motion sensing device) to generate visual fe ...

s ran at very low resolutions with a small number of colors, resulting in easily visible pixels. The resulting sharp edges gave curved objects and diagonal lines an unnatural appearance. However, when the number of available colors increased to 256, it was possible to gainfully employ anti-aliasing to smooth the appearance of low-resolution objects, not eliminating pixelation but making it less jarring to the eye. Higher resolutions would soon make this type of pixelation all but invisible on the screen, but pixelation is still visible if a low-resolution image is printed on paper. In the realm of real-time

3D computer graphics 3D computer graphics, sometimes called Computer-generated imagery, CGI, 3D-CGI or three-dimensional Computer-generated imagery, computer graphics, are graphics that use a three-dimensional representation of geometric data (often Cartesian coor ...

, pixelation can be a problem. Here, bitmaps are applied to polygons as

texture Texture may refer to: Science and technology * Image texture, the spatial arrangement of color or intensities in an image * Surface texture, the smoothness, roughness, or bumpiness of the surface of an object * Texture (roads), road surface c ...

s. As a camera approaches a textured polygon, simplistic nearest neighbor

texture filtering In computer graphics, texture filtering or texture smoothing is the method used to determine the texture color for a Texture mapping, texture mapped pixel, using the colors of nearby Texel (graphics), texels (ie. pixels of the texture). Filtering ...

would simply zoom in on the bitmap, creating drastic pixelation. The most common solution is a technique called ''pixel interpolation'' that smoothly blends or

interpolate In the mathematical field of numerical analysis, interpolation is a type of estimation, a method of constructing (finding) new data points based on the range of a discrete set of known data points. In engineering and science, one often has a ...

s the color of one pixel into the color of the next adjacent pixel at high levels of zoom. This creates a more organic, but also much blurrier image. Pixelation is a problem unique to bitmaps. Alternatives such as

vector graphics Vector graphics are a form of computer graphics in which visual images are created directly from geometric shapes defined on a Cartesian plane, such as points, lines, curves and polygons. The associated mechanisms may include vector displ ...

or purely geometric polygon models can scale to any level of detail. This is one reason vector graphics are popular for printing most modern computer monitors have a resolution of about 100 dots per inch, and at 300 dots per inch printed documents have about nine times as many pixels per unit of area as a screen. Another solution sometimes used is

procedural texture In computer graphics, a procedural texture is a Image texture, texture created using a mathematical description (i.e. an algorithm) rather than directly stored data. The advantage of this approach is low storage cost, unlimited texture resolution ...

s, textures such as

fractal In mathematics, a fractal is a Shape, geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scale ...

s that can be generated on-the-fly at arbitrary levels of detail.

Deliberate pixelation

In some cases, the resolution of an image or a portion of an image is lowered to introduce pixelation deliberately. This effect is commonly used on television news shows to obscure a person's face in order to protect their privacy or to censor

nudity Nudity is the state of being in which a human is without clothing. While estimates vary, for the first 90,000 years of pre-history, anatomically modern humans were naked, having lost their body hair, living in hospitable climates, and not ...

or vulgar gestures, and is also used for artistic effect. This effect is called ''

pixelization Pixelization (in British English pixelisation) or mosaic processing is any technique used in editing images or video, whereby an image is blurred by displaying part or all of it at a markedly lower resolution. It is primarily used for censorshi ...

''. Making pixels easily visible is also a main feature in pixel art which is where the graphics are made in low resolutions for effect.

Depixelization

''Depixelization'' removes pixelization from images, attempting to reconstruct the appearance of the original (unpixelated) image.

References

External links

Zooming Without Pixelation
digital camera advice by Mark Coffman
Pixelization of a Font
by

Stephen Wolfram Stephen Wolfram ( ; born 29 August 1959) is a British-American computer scientist, physicist, and businessman. He is known for his work in computer algebra and theoretical physics. In 2012, he was named a fellow of the American Mathematical So ...

The Wolfram Demonstrations Project The Wolfram Demonstrations Project is an open-source collection of interactive programmes called Demonstrations. It is hosted by Wolfram Research. At its launch, it contained 1300 demonstrations but has grown to over 10,000. The site won a Pa ...

. Computer graphic artifacts

Deliberate pixelation

Depixelization

See also

References

Further reading

External links