This example shows an image with a portion greatly enlarged, in which the individual pixels are rendered as little squares and can easily be seen.

In digital imaging, a pixel (picture element^[1]) is the smallest piece of information in an image. Pixels are normally arranged in a regular 2-dimensional grid, and are often represented using dots or squares. Each pixel is a sample of an original image, where more samples typically provide a more accurate representation of the original. The intensity of each pixel is variable; in color systems, each pixel has typically three or four components such as red, green, and blue, or cyan, magenta, yellow, and black. Pixel may refer to: Pixel, the base element of a digital image in computer graphics Pixel (musician), an Israeli psytrance musician Pixel (webcomic), a webcomic written by Chris Dlugosz Pixel image editor Daisuke Amaya, creator of freeware games Doukutsu Monogatari and Ikachan Category: ... Example of pixels in the (old) Wikipedia logo -- shows a zoomed section of the image to demonstrate how it is made up of pixels. ... Digital imaging or digital image acquisition is the creation of digital images, typically from a physical object. ... A sample refers to a value or set of values at a point in time and/or space. ... In physics, intensity is a measure of the time-averaged energy flux. ... RGB redirects here. ... Cyan, magenta, yellow, and key (black). ...

The word pixel is based on a contraction of pix (for "pictures") and el (for "element"); similar formations with el for "element" include voxel^[2], luxel,^{[citation needed]} and texel^[3]. A voxel (a portmanteau of the words volumetric and pixel) is a volume element, representing a value on a regular grid in three dimensional space. ... ...

Technical

A pixel does not need to be rendered as a small square. This image shows alternative ways of reconstructing an image from a set of pixel values, using dots, lines, or smooth filtering.

A pixel is generally thought of as the smallest single component of an image. The definition is highly context sensitive; for example, we can speak of printed pixels in a page, or pixels carried by electronic signals, or represented by digital values, or pixels on a display device, or pixels in a digital camera (photosensor elements). This list is not exhaustive, and depending on context there are several terms that are synonymous in particular contexts, e.g. pel, sample, byte, bit, dot, spot, etc. We can also speak of pixels in the abstract, or as a unit of measure, in particular when using pixels as a measure of resolution, e.g. 2400 pixels per inch, 640 pixels per line, or spaced 10 pixels apart. Image File history File links ReconstructionsFromPixels. ... Dots has several meanings Dots and Boxes (also known as Boxes, Squares, Square-it or Dots) is a pencil and paper game for two players (or sometimes, more than two). ...

The measures dots per inch (dpi) and pixels per inch (ppi) are sometimes used interchangeably, but have distinct meanings especially in the printer field, where dpi is a measure of the printer's resolution of dot printing (e.g. ink droplet density). For example, a high-quality inkjet image may be printed with 200 ppi on a 720 dpi printer. Dots per inch (DPI) is a measure of printing resolution, in particular the number of individual dots of ink a printer or toner can produce within a linear one-inch (2. ... The square shown above is 200 pixels by 200 pixels. ...

The more pixels used to represent an image, the closer the result can resemble the original. The number of pixels in an image is sometimes called the resolution, though resolution has a more specific definition. Pixel counts can be expressed as a single number, as in a "three-megapixel" digital camera, which has a nominal three million pixels, or as a pair of numbers, as in a "640 by 480 display", which has 640 pixels from side to side and 480 from top to bottom (as in a VGA display), and therefore has a total number of 640 × 480 = 307,200 pixels or 0.3 megapixels. Image resolution describes the detail an image holds. ... Look up digital camera in Wiktionary, the free dictionary. ... Video Graphics Array (VGA) is a computer display standard first marketed in 1987 by IBM. VGA belongs to a family of earlier IBM video standards and largely remains backward compatible with them. ...

The pixels, or color samples, that form a digitized image (such as a JPEG file used on a web page) may or may not be in one-to-one correspondence with screen pixels, depending on how a computer displays an image. JPG redirects here. ... Correspondence may refer to: In the theology of Emanuel Swedenborg, correspondence is the relationship between spiritual and physical realities. ...

In computing, an image composed of pixels is known as a bitmapped image or a raster image. The word raster originates from television scanning patterns, and has been widely used to describe similar halftone printing and storage techniques. This article is about the storage organization of raster images. ... Imagine the smiley face in the top left corner as an RGB bitmap image. ... Raster can refer to either of the following items: Raster graphics, Bit array, the general-purpose data structure, or The scanning pattern of the electron beam to a screen of a Cathode Ray Tube. ... Left: halftone spots. ...

Sampling patterns

For convenience, pixels are normally arranged in a regular two dimensional grid. By using this arrangement, many common operations can be implemented by uniformly applying the same operation to each pixel independently. Example of regular grid. ...

Other arrangements of pixels are also possible, with some sampling patterns even changing the shape (or kernel) of each pixel across the image. In mathematics and, in particular, functional analysis, convolution is a mathematical operator which takes two functions f and g and produces a third function that in a sense represents the amount of overlap between f and a reversed and translated version of g. ...

For this reason, care must be taken when acquiring an image on one device and displaying it on another, or when converting image data from one pixel format to another.

For example:

• LCD screens typically use a staggered grid, where the red, green, and blue components are sampled at slightly different locations. Cleartype is a technology which takes advantage of these differences to improve the rendering of text on LCD screens.
• Some digital cameras use a Bayer filter, resulting in a regular grid of pixels where the color of each pixel depends on its position on the grid.
• A clipmap uses a hierarchical sampling pattern, where the size of the support of each pixel depends on its location within the hierarchy.
• Warped grids are used when the underlying geometry is non-planar, such as images of the earth from space.^[4]
• The use of non-uniform grids is an active research area, attempting to bypass the traditional Nyquist limit.^[5]
• Pixels on computer monitors are normally square, but some digital video formats have non-square aspect ratios, such as the anamorphic widescreen formats of the CCIR 601 digital video standard.

LCD redirects here. ... ClearType is a registered trademark for a technology developed by Microsoft Corporation to improve the appearance of text on certain types of computer display screens, especially flat-panel displays. ... The Bayer arrangement of color filters on the pixel array of an image sensor Front page of Dr. Bryce Bayers 1976 patent on the Bayer pattern filter mosaic, showing his terminology of luminance-sensitive and chrominance-sensitive elements A Bayer filter mosaic is a color filter array (CFA) for... Clipmapping is a method of clipping a mipmap to a subset of data pertinent to the geometry being displayed. ... In mathematics, the support of a real-valued function f on a set X is sometimes defined as the subset of X on which f is nonzero. ... The sampling frequency or sampling rate defines the number of samples per second taken from a continuous signal to make a discrete signal. ... Digital video is a type of video recording system that works by using a digital, rather than analog, of the video signal. ... The term pixel aspect ratio, sometimes shortened to aspect ratio, is also used in the context of computer graphics to describe the distribution of pixel in a digitized image. ... For the film format, see anamorphic format. ... CCIR 601 is the old name of a standard published by the CCIR (now ITU-R) for encoding interlaced analogue video signals in digital form. ...

Display resolution vs. native resolution in computer monitors

Computers can use pixels to display an image, often an abstract image that represents a GUI. The resolution of this image is called the display resolution and is determined by the video card of the computer. GUI can refer to the following: GUI is short for graphical user interface, a term used to describe a type of interface in computing. ... A video card, also referred to as a graphics accelerator card, display adapter, graphics card, and numerous other terms, is an item of personal computer hardware whose function is to generate and output images to a display. ...

Modern computer monitors also use pixels to display an image, and have a native resolution. In the case of an LCD monitor, each pixel is made up of triads, with the number of these triads determining the native resolution. On some CRT monitors, the beam sweep rate may be fixed, resulting in a fixed native resolution. LCD redirects here. ... For other meanings see Triad (disambiguation). ... Cathode ray tube employing electromagnetic focus and deflection Cutaway rendering of a color CRT: 1. ...

To produce the sharpest images possible, the user must ensure the display resolution of the computer matches the native resolution of the monitor.

If these resolutions are different, the image may appear squashed or stretched, or the monitor may resample the image, resulting in a blurry or jagged appearance. For resampling methods in statistics, see Resampling (statistics). ...

Bits per pixel

Main article: Color depth

The number of distinct colors that can be represented by a pixel depends on the number of bits per pixel (bpp). A 1 bpp image uses 1 bit for each pixel, so each pixel can be either on or off. Each additional bit doubles the number of colors available, so a 2 bpp image can have 4 colors, and a 3 bpp image can have 8 colors: Color depth is a computer graphics term describing the number of bits used to represent the color of a single pixel in a bitmapped image or video frame buffer. ...

• 1 bpp, 2¹ = 2 colors (monochrome)
• 2 bpp, 2² = 4 colors
• 3 bpp, 2³ = 8 colors

...

• 8 bpp, 2⁸ = 256 colors
• 16 bpp, 2¹⁶ = 65,536 colors ("Highcolor" )
• 24 bpp, 2²⁴ ≈ 16.7 million colors ("Truecolor")

For color depths of 15 or more bits per pixel, the depth is normally the sum of the bits allocated to each of the red, green, and blue components. Highcolor, usually meaning 16 bpp, normally has five bits for red and blue, and six bits for green, as the human eye is more sensitive to errors in green than in the other two primary colors. For applications involving transparency, the 16 bits may be divided into five bits each of red, green, and blue, with one bit left for transparency. A 24-bit depth allows 8 bits per component. On some systems, 32-bit depth is available: this means that each 24-bit pixel has an extra 8 bits to describe its opacity (for purposes of combining with another image). Highcolor graphics (variously spelled Hicolor , Hicolour, and Highcolour, and known as Thousands of colors on a Macintosh) is a method of storing image information in a computers memory such that each pixel is represented by two bytes. ... Truecolor (also spelled Truecolour; called Millions on a Macintosh) graphics is a method of storing image information in a computers memory such that each pixel is represented by three or more bytes. ... Highcolor graphics (variously spelled Hicolor , Hicolour, and Highcolour, and known as Thousands of colors on a Macintosh) is a method of storing image information in a computers memory such that each pixel is represented by two bytes. ... A substance or object that is opaque is neither transparent nor translucent. ...

Subpixels

Phosphor dots in a color CRT display bear no relation to pixels or subpixels

Pixel geometry of various CRT and LCD displays.

Many display and image-acquisition systems are, for various reasons, not capable of displaying or sensing the different color channels at the same site. Therefore, the pixel grid is divided into single-color regions that contribute to the displayed or sensed color when viewed at a distance. Image File history File links Size of this preview: 700 × 508 pixelsFull resolution (700 × 508 pixel, file size: 518 KB, MIME type: image/png) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Size of this preview: 700 × 508 pixelsFull resolution (700 × 508 pixel, file size: 518 KB, MIME type: image/png) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Green screen A phosphor is a substance that exhibits the phenomenon of phosphorescence (sustained glowing after exposure to light or energised particles such as electrons). ... Image File history File links Size of this preview: 600 × 600 pixelsFull resolution‎ (1,100 × 1,100 pixels, file size: 195 KB, MIME type: image/jpeg) Photo credit: Peter Halasz. ... Image File history File links Size of this preview: 600 × 600 pixelsFull resolution‎ (1,100 × 1,100 pixels, file size: 195 KB, MIME type: image/jpeg) Photo credit: Peter Halasz. ... The components of the pixels (primary colors red, green and blue) in an image sensor or display can be ordered in different patterns, called pixel geometry. ... Color is an important part of the visual arts. ...

In some displays, such as LCD, LED, and plasma displays, these single-color regions are separately addressable elements, which have come to be known as subpixels. For example, LCDs typically divide each pixel horizontally into three subpixels. LCD redirects here. ...

Most digital camera image sensors also use single-color sensor regions, for example using the Bayer filter pattern, but in the case of cameras these are known as pixels, not subpixels. Look up digital camera in Wiktionary, the free dictionary. ... A dismantled USB webcam, with and without a lens over its (Bayer format) image sensor. ... The Bayer arrangement of color filters on the pixel array of an image sensor Front page of Dr. Bryce Bayers 1976 patent on the Bayer pattern filter mosaic, showing his terminology of luminance-sensitive and chrominance-sensitive elements A Bayer filter mosaic is a color filter array (CFA) for...

For systems with subpixels, two different approaches can be taken:

• The subpixels can be ignored, with full-color pixels being treated as the smallest addressable imaging element; or
• The subpixels can be included in rendering calculations, which requires more analysis and processing time, but can produce apparently superior images in some cases.

The latter approach has been used to increase the apparent resolution of color displays. The technique, referred to as subpixel rendering, uses knowledge of pixel geometry to manipulate the three colored subpixels separately and produce a better displayed image. Subpixel rendering works by increasing the luminance reconstruction points of a color subpixelated screen, such as a liquid crystal display (LCD). ... The components of the pixels (primary colors red, green and blue) in an image sensor or display can be ordered in different patterns, called pixel geometry. ...

While CRT displays also use red-green-blue masked phosphor areas, dictated by a mesh grid called the shadow mask, these can not be aligned with the displayed pixel raster, and therefore can not be utilised for subpixel rendering. Cathode ray tube employing electromagnetic focus and deflection Cutaway rendering of a color CRT: 1. ...

Megapixel

A megapixel is 1 million pixels, and is a term used not only for the number of pixels in an image, but also to express the number of image sensor elements of digital cameras or the number of display elements of digital displays. For example, a camera with an array of 2048×1536 sensor elements is commonly said to have "3.1 megapixels" (2048 × 1536 = 3,145,728). The neologism sensel is sometimes used to describe the elements of a digital camera's sensor, since these are picture-detecting rather than picture-producing elements.^[6] A dismantled USB webcam, with and without a lens over its (Bayer format) image sensor. ... Look up digital camera in Wiktionary, the free dictionary. ... A computer display monitor, usually called simply a monitor, is a piece of electrical equipment which displays viewable images generated by a computer without producing a permanent record. ...

Digital cameras use photosensitive electronics, either charge-coupled device (CCD) or complementary metal–oxide–semiconductor (CMOS) image sensors, consisting of a large number of single sensor elements, each of which records a measured intensity level. In most digital cameras, the sensor array is covered with a patterned color filter mosaic having red, green, and blue regions in the Bayer filter arrangement, so that each sensor element can record the intensity of a single primary color of light. The camera interpolates the color information of neighboring sensor elements, through a process called demosaicing, to create the final image. These sensor elements are often called "pixels", even though they only record 1 channel (only red, or green, or blue) of the final color image. Thus, two of the three color channels for each sensor must be interpolated and a so-called N-megapixel camera that produces an N-megapixel image provides only one-third of the information that an image of the same size could get from a scanner. Thus, certain color contrasts may look fuzzier than others, depending on the allocation of the primary colors (green has twice as many elements as red or blue in the Bayer arrangement). A specially developed CCD used for ultraviolet imaging in a wire bonded package. ... For other uses, see CMOS (disambiguation). ... A dismantled USB webcam, with and without a lens over its (Bayer format) image sensor. ... The Bayer arrangement of color filters on the pixel array of an image sensor Front page of Dr. Bryce Bayers 1976 patent on the Bayer pattern filter mosaic, showing his terminology of luminance-sensitive and chrominance-sensitive elements A Bayer filter mosaic is a color filter array (CFA) for... A demosaicing algorithm is a digital image process used to interpolate a complete image from the partial raw data received from the color-filtered image sensor internal to many digital cameras in form of a matrix of colored pixels. ...

In contrast to conventional image sensors, the Foveon X3 sensor uses three layers of sensor elements, so that it detects red, green, and blue intensity at each array location. This structure eliminates the need for de-mosaicing and eliminates the associated image artifacts, such as color blurring around sharp edges. Citing the precedent established by mosaic sensors, Foveon counts each single-color sensor element as a pixel, even though the native output file size has only one pixel per three camera pixels.[1] With this method of counting, an N-megapixel Foveon X3 sensor therefore captures the same amount of information as an N-megapixel Bayer-mosaic sensor, though it packs the information into fewer image pixels, without any interpolation. The Foveon X3 sensor is an image sensor for digital cameras produced by Foveon, Inc. ...

Standard display resolutions

Main article: display resolution

Display standards comparison

Selected standard display resolutions include: Display standards comparison The display resolution of a digital television or computer display typically refers to the number of distinct pixels in each dimension that can be displayed. ... Image File history File links Vector_Video_Standards2. ... Image File history File links Vector_Video_Standards2. ...

The 640×200 2 color mode with its default foreground color — Arachne Internet suite. ... The Enhanced Graphics Adapter (EGA) is the IBM PC computer display standard specification located between CGA and VGA in terms of graphics performance (that is, colour and space resolution). ... Video Graphics Array (VGA) is a computer display standard first marketed in 1987 by IBM. VGA belongs to a family of earlier IBM video standards and largely remains backward compatible with them. ... Super Video Graphics Array, almost always abbreviated to Super VGA or just SVGA is a broad term that covers a wide range of computer display standards. ... XGA, the eXtended Graphics Array, is an IBM display standard introduced in 1990. ... SXGA (5:4) compared with the other display standards. ... UXGA is an abbreviation for Ultra eXtended Graphics Accelerator referring to a standard monitor resolution of 1600 × 1200 pixels, which is exactly quadruple the default resolution of SVGA (800 × 600). ...

Etymology

The word pixel was first published in 1965 by Frederic C. Billingsley of JPL, to describe the picture elements of video images from space probes to the moon and Mars; but he did not coin the term himself, and the person he got it from (Keith E. McFarland at the Link Division of General Precision in Palo Alto) does not know where he got it, but says it was "in use at the time" (circa 1963). Fred Billingsley, circa 1964 Frederic Crockett Billingsley (23 July 1921 – 31 May 2002) was an American engineer, who spent most of his career developing techniques for digital image processing in support of American space probes to the moon, to Mars, and to other planets. ... For the singer/songwriter, see Jon Peter Lewis. ...

The word is a combination of picture and element, via pix. Pix was first coined in 1932 in a Variety Magazine headline, as an abbreviation for the word pictures, in reference to movies; by 1938 pix was being used in reference to still pictures by photojournalists. Variety is a daily magazine for the entertainment industry. ...

The concept of a picture element dates to the earliest days of television, for example as Bildpunkt (the German word for pixel, literally picture point) in the 1888 German patent of Paul Nipkow. According to various etymologies, the earliest publication of the term picture element itself was in Wireless World magazine in 1927,^[7]though it had been used earlier in various U.S. patents filed as early as 1911.[2] Paul Gottlieb Nipkow (August 22, 1860 - August 24, 1940) was a German engineer, who devised a mechanical apparatus, a spinning disk to scan images that was used in early television. ...

Some authors explain pixel as picture cell, as early as 1972.^[8]

A detailed history of pixel and picture element, with references, is linked below.

In video processing, Pel is often used instead of pixel. For example, IBM used it in their Technical Reference for the original PC.^[9] IBM PC (IBM 5150) with keyboard and green screen monochrome monitor (IBM 5151), running MS-DOS 5. ...

Words with similar etymologies

Texel (texture element) and Luxel (Lux Element) are words used to describe a pixel when it is used in specific context (texturing and light mapping respectively) ... The lux (symbol: lx) is the SI derived unit of illuminance or illumination. ...

A voxel is a volume element, the 3D analogue of a 2D Pixel. A voxel (a portmanteau of the words volumetric and pixel) is a volume element, representing a value on a regular grid in three dimensional space. ...

Surfels (surface elements) have the same naming pattern as pixels, but share more similarities with shrunken triangles than expanded pixels. Polygons are used in computer graphics to compose images that are three-dimensional in appearance. ...

See also

Various computer display standards or display modes have been used in the history of the personal computer. ... Image resolution describes the detail an image holds. ... Raster can refer to either of the following items: Raster graphics, Bit array, the general-purpose data structure, or The scanning pattern of the electron beam to a screen of a Cathode Ray Tube. ... Example showing effect of vector graphics versus raster graphics. ... Rasterization or rasterisation is the task of taking an image described in a vector graphics format (shapes) and converting it into a raster image (pixels or dots) for output on a video display or printer. ... This monster (The Gunk) is an example of pixel art drawn using Microsoft Paint. ... ‹ The template below (Expand) is being considered for deletion. ... Gigapixel image of Balboa Park (saved for web) from Gigapxl Project. ... This article is about Web advertising. ... CMOS sensor processing is done in pixel level. ... Pixel overdrive is a method used to make video on LCD screens look better. ... The term pixel aspect ratio, sometimes shortened to aspect ratio, is also used in the context of computer graphics to describe the distribution of pixel in a digitized image. ...

References

Pearson can mean Pearson PLC the media conglomerate. ... Pearson can mean Pearson PLC the media conglomerate. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Common Era (or Anno Domini), in accordance with the Gregorian calendar. ... is the 129th day of the year (130th in leap years) in the Gregorian calendar. ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Common Era (or Anno Domini), in accordance with the Gregorian calendar. ... is the 129th day of the year (130th in leap years) in the Gregorian calendar. ... The New York Times is a daily newspaper published in New York City and distributed internationally. ... is the 92nd day of the year (93rd in leap years) in the Gregorian calendar. ... Year 1995 (MCMXCV) was a common year starting on Sunday. ... April 7 is the 97th day of the year in the Gregorian calendar (98th in leap years). ... 2008 (MMVIII) is the current year, a leap year that started on Tuesday of the Common Era (or Anno Domini), in accordance with the Gregorian calendar. ...

External links

• A Pixel Is Not A Little Square: Microsoft Memo by computer graphics pioneer Alvy Ray Smith.
• A Brief History of 'Pixel': More than you need to know about the history of pixel, pel, and picture element.
• Pixels and Me: Video of a history talk at the Computer History Museum.
• Square and non-Square Pixels: Technical info on pixel aspect ratios of modern video standards (480i,576i,1080i,720p), plus software implications.