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

, pixelation (or pixellation in

British English British English (BrE, en-GB, or BE) is, according to Oxford Dictionaries, "English as used in Great Britain, as distinct from that used elsewhere". More narrowly, it can refer specifically to the English language in England, or, more broadl ...

) is caused by displaying a

bitmap In computing, a bitmap is a mapping from some domain (for example, a range of integers) to bits. It is also called a bit array or bitmap index. As a noun, the term "bitmap" is very often used to refer to a particular bitmapping application: t ...

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 image, or the smallest point in an all points addressable display device. In most digital display devices, pixels are the ...

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 Video games, also known as computer games, are electronic games that involves interaction with a user interface or input device such as a joystick, controller, keyboard, or motion sensing device to generate visual feedback. This feedba ...

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, or “3D graphics,” sometimes called CGI, 3D-CGI or three-dimensional computer graphics are graphics that use a three-dimensional representation of geometric data (often Cartesian) that is stored in the computer for th ...

, pixelation can be a problem. Here, bitmaps are applied to polygons as textures. 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 mapped pixel, using the colors of nearby texels (pixels of the texture). There are two main categories of texture filterin ...

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 ...

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. There are a number of ways of doing this; see ''

'' for details. Pixelation is a problem unique to bitmaps. Alternatives such as

vector graphics Vector graphics is 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 display ...

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 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 and easy text ...

s, textures such as

fractal In mathematics, a fractal is a 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 scales, as ill ...

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 or to censor

nudity Nudity is the state of being in which a human is without clothing. The loss of body hair was one of the physical characteristics that marked the biological evolution of modern humans from their hominin ancestors. Adaptations related to h ...

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

pixelization Pixelization (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 Pixel art () is a form of digital art drawn with graphical software where images are built using pixels as the only building block. It is widely associated with the low-resolution graphics from 8-bit and 16-bit era computers and arcade video g ...

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

{{reflist

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 science, mathematics, and theoretical physics. In 2012, he was named a fellow of the American Ma ...

, The Wolfram Demonstrations Project. Computer graphic artifacts

Deliberate pixelation

Depixelization

See also

References

External links