![Closeup of pixels](https://upload.wikimedia.org/wikipedia/commons/d/de/Closeup_of_pixels.JPG)
In
digital imaging
Digital imaging or digital image acquisition is the creation of a digital representation of the visual characteristics of an object, such as a physical scene or the interior structure of an object. The term is often assumed to imply or include ...
, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a
raster image
upright=1, The Smiley, smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for ...
, or the smallest point in an
all points addressable
A dot matrix is a 2-dimensional patterned array, used to represent characters, symbols and images. Most types of modern technology use dot matrices for display of information, including mobile phones, televisions, and printers. The system is al ...
display device
A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...
.
In most digital
display device
A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signal the ...
s, pixels are the smallest element that can be manipulated through software.
Each pixel is a
sample
Sample or samples may refer to:
Base meaning
* Sample (statistics), a subset of a population – complete data set
* Sample (signal), a digital discrete sample of a continuous analog signal
* Sample (material), a specimen or small quantity of s ...
of an original image; more samples typically provide more accurate representations of the original. The
intensity
Intensity may refer to:
In colloquial use
*Strength (disambiguation)
*Amplitude
* Level (disambiguation)
* Magnitude (disambiguation)
In physical sciences
Physics
*Intensity (physics), power per unit area (W/m2)
*Field strength of electric, ma ...
of each pixel is variable. In color imaging systems, a color is typically represented by three or four component intensities such as
red, green, and blue, or
cyan, magenta, yellow, and black.
In some contexts (such as descriptions of
camera sensor
An image sensor or imager is a sensor that detects and conveys information used to make an image. It does so by converting the variable attenuation of light waves (as they pass through or reflect off objects) into signals, small bursts of curr ...
s), ''pixel'' refers to a single scalar element of a multi-component representation (called a ''photosite'' in the camera sensor context, although ''
sensel
Sensel is an electronics company based in Sunnyvale, California that builds touch input technologies . It was founded in 2013 by former Amazon engineers Ilya Rosenberg and Aaron Zarraga. Sensel's first product, the Morph, is a pressure sensitive ...
'' is sometimes used), while in yet other contexts (like MRI) it may refer to a set of component intensities for a spatial position.
Etymology
The word ''pixel'' is a combination of ''pix'' (from "pictures", shortened to "pics") and ''el'' (for "''
element''"); similar formations with '
''el include the words ''
voxel
In 3D computer graphics, a voxel represents a value on a regular grid in three-dimensional space. As with pixels in a 2D bitmap, voxels themselves do not typically have their position (i.e. coordinates) explicitly encoded with their values. Ins ...
''
and
''texel''.
[ The word ''pix'' appeared in '']Variety
Variety may refer to:
Arts and entertainment Entertainment formats
* Variety (radio)
* Variety show, in theater and television
Films
* ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont
* ''Variety'' (1935 film), ...
'' magazine headlines in 1932, as an abbreviation for the word ''pictures'', in reference to movies. By 1938, "pix" was being used in reference to still pictures by photojournalists.[
The word "pixel" was first published in 1965 by ]Frederic C. Billingsley
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.
...
of JPL
The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States.
Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...
, to describe the picture elements of scanned images from space probe
A space probe is an artificial satellite that travels through space to collect scientific data. A space probe may orbit Earth; approach the Moon; travel through interplanetary space; flyby, orbit, or land or fly on other planetary bodies; or ent ...
s to the Moon and Mars. Billingsley had learned the word from Keith E. McFarland, at the Link Division of General Precision in Palo Alto
Palo Alto (; Spanish for "tall stick") is a charter city in the northwestern corner of Santa Clara County, California, United States, in the San Francisco Bay Area, named after a coastal redwood tree known as El Palo Alto.
The city was estab ...
, who in turn said he did not know where it originated. McFarland said simply it was "in use at the time" (circa 1963).
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
Paul Julius Gottlieb Nipkow (22 August 1860 – 24 August 1940) was a German technician and inventor. He invented the Nipkow disk, which laid the foundation of television, since his disk was a fundamental component in the first televisions. Hun ...
. According to various etymologies, the earliest publication of the term ''picture element'' itself was in ''Wireless World
''Electronics World'' (''Wireless World'', founded in 1913, and in September 1984 renamed ''Electronics & Wireless World'') is a technical magazine in electronics and RF engineering aimed at professional design engineers. It is produced monthly in ...
'' magazine in 1927, though it had been used earlier in various U.S. patents filed as early as 1911.
Some authors explain ''pixel'' as ''picture cell,'' as early as 1972. In graphics
Graphics () are visual images or designs on some surface, such as a wall, canvas, screen, paper, or stone, to inform, illustrate, or entertain. In contemporary usage, it includes a pictorial representation of data, as in design and manufacture ...
and in image and video processing, ''pel'' is often used instead of ''pixel''. For example, IBM used it in their Technical Reference for the original PC.
Pixilation
Pixilation is a stop motion technique in which live actors are used as a frame-by-frame subject in an animated film, by repeatedly posing while one or more frame is taken and changing pose slightly before the next frame or frames. The actor beco ...
, spelled with a second ''i'', is an unrelated filmmaking technique that dates to the beginnings of cinema, in which live actors are posed frame by frame and photographed to create stop-motion animation. An archaic British word meaning "possession by spirits (pixie
A pixie (also pisky, pixy, pixi, pizkie, and piskie in Cornwall and Devon, and pigsie or puggsy in the New Forest) is a mythical creature of British folklore. Pixies are considered to be particularly concentrated in the high moorland areas arou ...
s)", the term has been used to describe the animation process since the early 1950s; various animators, including Norman McLaren
William Norman McLaren, LL. D. (11 April 1914 – 27 January 1987) was a Scottish Canadian animator, director and producer known for his work for the National Film Board of Canada (NFB).Rosenthal, Alan. ''The new documentary in action: a caseb ...
and Grant Munro, are credited with popularizing it.
Technical
thought of as the smallest single component of a digital image
A digital image is an image composed of picture elements, also known as ''pixels'', each with ''finite'', '' discrete quantities'' of numeric representation for its intensity or gray level that is an output from its two-dimensional functions ...
. However, the definition is highly context-sensitive. For example, there can be " 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
A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile device ...
(photosensor elements). This list is not exhaustive and, depending on context, synonyms include pel, sample, byte, bit, dot, and spot. ''Pixels'' can be used as a unit of measure such as: 2400 pixels per inch, 640 pixels per line, or spaced 10 pixels apart.
The measures dots per inch
Dots per inch (DPI, or dpiThe acronym appears in sources as either "DPI" or lowercase "dpi". See "Print Resolution Understanding 4-bit depth – Xerox" (PDF). Xerox.com. September 2012.) is a measure of spatial printing, video or image scanner ...
(dpi) and pixels per inch
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 smal ...
(ppi) are sometimes used interchangeably, but have distinct meanings, especially for printer devices, where dpi is a measure of the printer's density of dot (e.g. ink droplet) placement. For example, a high-quality photographic image may be printed with 600 ppi on a 1200 dpi inkjet printer. Even higher dpi numbers, such as the 4800 dpi quoted by printer manufacturers since 2002, do not mean much in terms of achievable resolution
Resolution(s) may refer to:
Common meanings
* Resolution (debate), the statement which is debated in policy debate
* Resolution (law), a written motion adopted by a deliberative body
* New Year's resolution, a commitment that an individual mak ...
.
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
Video Graphics Array (VGA) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the PC industry within three years. The term can no ...
display) and therefore has a total number of 640 × 480 = 307,200 pixels, or 0.3 megapixels.
The pixels, or color samples, that form a digitized image (such as a JPEG
JPEG ( ) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and imag ...
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. In computing, an image composed of pixels is known as a '' bitmapped image'' or a ''raster image
upright=1, The Smiley, smiley face in the top left corner is a raster image. When enlarged, individual pixels appear as squares. Enlarging further, each pixel can be analyzed, with their colors constructed through combination of the values for ...
''. The word ''raster'' originates from television scanning patterns, and has been widely used to describe similar halftone
Halftone is the reprographic
Reprography (a portmanteau of ''reproduction'' and ''photography'') is the reproduction of graphics through mechanical or electrical means, such as photography or xerography. Reprography is commonly used in catal ...
printing and storage techniques.
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. Other arrangements of pixels are possible, with some sampling patterns even changing the shape (or kernel
Kernel may refer to:
Computing
* Kernel (operating system), the central component of most operating systems
* Kernel (image processing), a matrix used for image convolution
* Compute kernel, in GPGPU programming
* Kernel method, in machine learnin ...
) of each pixel across the image. 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
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...
typically use a staggered grid, where the red, green, and blue components are sampled at slightly different locations. Subpixel rendering
Subpixel rendering is a way to increase the apparent resolution of a computer's liquid crystal display (LCD) or organic light-emitting diode (OLED) display by rendering pixels to take into account the screen type's physical properties. It takes ...
is a technology which takes advantage of these differences to improve the rendering of text on LCD screens.
* The vast majority of color digital cameras use a Bayer filter
A Bayer filter mosaic is a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, camco ...
, resulting in a regular grid of pixels where the ''color'' of each pixel depends on its position on the grid.
* A clipmap Clipmapping is a method of clipping a mipmap to a subset of data pertinent to the geometry being displayed. This is useful for loading as little data as possible when memory is limited, such as on a graphics processing unit
A graphics processing ...
uses a hierarchical sampling pattern, where the size of the support
Support may refer to:
Arts, entertainment, and media
* Supporting character
Business and finance
* Support (technical analysis)
* Child support
* Customer support
* Income Support
Construction
* Support (structure), or lateral support, a ...
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.
* The use of non-uniform grids is an active research area, attempting to bypass the traditional Nyquist limit
In signal processing, the Nyquist frequency (or folding frequency), named after Harry Nyquist, is a characteristic of a sampler, which converts a continuous function or signal into a discrete sequence. In units of cycles per second ( Hz), it ...
.
* Pixels on computer monitors are normally "square" (that is, have equal horizontal and vertical sampling pitch); pixels in other systems are often "rectangular" (that is, have unequal horizontal and vertical sampling pitch – oblong in shape), as are digital video
Digital video is an electronic representation of moving visual images (video) in the form of encoded digital data. This is in contrast to analog video, which represents moving visual images in the form of analog signals. Digital video comprises ...
formats with diverse aspect ratios, such as the anamorphic widescreen
Anamorphic widescreen (also called Full height anamorphic or FHA) is a process by which a comparatively wide widescreen image is horizontally compressed to fit into a storage medium (photographic film or MPEG-2 standard-definition frame, for exam ...
formats of the Rec. 601
ITU-R Recommendation BT.601, more commonly known by the abbreviations Rec. 601 or BT.601 (or its former name CCIR 601) is a standard originally issued in 1982 by the CCIR (an organization, which has since been renamed as the Internatio ...
digital video standard.
Resolution of computer monitors
Computers can use pixels to display an image, often an abstract image that represents a GUI
The GUI ( "UI" by itself is still usually pronounced . or ), graphical user interface, is a form of user interface that allows users to interact with electronic devices through graphical icons and audio indicator such as primary notation, inste ...
. The resolution of this image is called the display resolution and is determined by the 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 moni ...
of the computer. LCD
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...
monitors also use pixels to display an image, and have a native resolution
The native resolution of an LCD, LCoS or other flat panel display refers to its single fixed resolution. As an LCD consists of a fixed raster, it cannot change resolution to match the signal being displayed, while black and white CRT 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. Most CRT monitors do not have a fixed beam sweep rate, meaning they do not have a native resolution at all - instead they have a set of resolutions that are equally well supported.To produce the sharpest images possible on an LCD, the user must ensure the display resolution of the computer matches the native resolution of the monitor.
Resolution of telescopes
The pixel scale used in astronomy
Astronomy () is a natural science that studies astronomical object, celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and chronology of the Universe, evolution. Objects of interest ...
is the angular distance between two objects on the sky that fall one pixel apart on the detector (CCD or infrared chip). The scale measured in radian
The radian, denoted by the symbol rad, is the unit of angle in the International System of Units (SI) and is the standard unit of angular measure used in many areas of mathematics. The unit was formerly an SI supplementary unit (before that c ...
s is the ratio of the pixel spacing and focal length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative foca ...
of the preceding optics, . (The focal length is the product of the focal ratio
In optics, the f-number of an optical system such as a camera lens is the ratio of the system's focal length to the diameter of the entrance pupil ("clear aperture").Smith, Warren ''Modern Optical Engineering'', 4th Ed., 2007 McGraw-Hill P ...
by the diameter of the associated lens or mirror.)
Because is usually expressed in units of arcseconds
A minute of arc, arcminute (arcmin), arc minute, or minute arc, denoted by the symbol , is a unit of angular measurement equal to of one degree. Since one degree is of a turn (or complete rotation), one minute of arc is of a turn. The na ...
per pixel, because 1 radian equals (180/π) × 3600 ≈ 206,265 arcseconds, and because focal lengths are often given in millimeters and pixel sizes in micrometers which yields another factor of 1,000, the formula is often quoted as .
Bits per pixel
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:
* 1 bpp, 21 = 2 colors (monochrome
A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, monochrom ...
)
* 2 bpp, 22 = 4 colors
* 3 bpp, 23 = 8 colors
* 4 bpp, 24 = 16 colors
* 8 bpp, 28 = 256 colors
* 16 bpp, 216 = 65,536 colors ("Highcolor
High color graphics is a method of storing image information in a computer's memory such that each pixel is represented by two bytes. Usually the color is represented by all 16 bits, but some devices also support 15-bit high color.
More recently ...
" )
* 24 bpp, 224 = 16,777,216 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
High color graphics is a method of storing image information in a computer's memory such that each pixel is represented by two bytes. Usually the color is represented by all 16 bits, but some devices also support 15-bit high color.
More recently ...
, usually meaning 16 bpp, normally has five bits for red and blue each, 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).
Subpixels
Many display and image-acquisition systems are 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. 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, mostly RGB
The RGB color model is an additive color model in which the red, green and blue primary colors of light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additiv ...
colors. For example, LCD
A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers. Liquid crystals do not emit light directly but in ...
s typically divide each pixel vertically into three subpixels. When the square pixel is divided into three subpixels, each subpixel is necessarily rectangular. In display industry terminology, subpixels are often referred to as ''pixels'', as they are the basic addressable elements in a viewpoint of hardware, and hence ''pixel circuits'' rather than ''subpixel circuits'' is used.
Most digital camera image sensor
An image sensor or imager is a sensor that detects and conveys information used to make an image. It does so by converting the variable attenuation of light waves (as they pass through or reflect off objects) into signals, small bursts of curr ...
s use single-color sensor regions, for example using the Bayer filter
A Bayer filter mosaic is a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, camco ...
pattern, and in the camera industry these are known as ''pixels'' just like in the display industry, not ''subpixels''.
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.
This latter approach, referred to as subpixel rendering
Subpixel rendering is a way to increase the apparent resolution of a computer's liquid crystal display (LCD) or organic light-emitting diode (OLED) display by rendering pixels to take into account the screen type's physical properties. It takes ...
, uses knowledge of pixel geometry
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.
The geometric arrangement of the primary colors within a pixel varies depending on usage ...
to manipulate the three colored subpixels separately, producing an increase in the apparent resolution of color displays. While CRT displays use red-green-blue-masked phosphor areas, dictated by a mesh grid called the shadow mask, it would require a difficult calibration step to be aligned with the displayed pixel raster, and so CRTs do not use subpixel rendering.
The concept of subpixels is related to samples.
Logical pixel
In graphic, web design, and user interfaces, a "pixel" may refer to a fixed length rather than a true pixel on the screen to accommodate different pixel densities
Pixels per inch (ppi) and pixels per centimetre (ppcm or pixels/cm) are measurements of the pixel density of an electronic image device, such as a computer monitor or television display, or image digitizing device such as a camera or image scanner ...
. A typical definition, such as in CSS
Cascading Style Sheets (CSS) is a style sheet language used for describing the presentation of a document written in a markup language such as HTML or XML (including XML dialects such as SVG, MathML or XHTML). CSS is a cornerstone techno ...
, is that a "physical" pixel is . Doing so makes sure a given element will display as the same size no matter what screen resolution views it.
There may, however, be some further adjustments between a "physical" pixel and an on-screen logical pixel. As screens are viewed at difference distances (consider a phone, a computer display, and a TV), the desired length (a "reference pixel") is scaled relative to a reference viewing distance ( in CSS). In addition, as true screen pixel densities are rarely multiples of 96 dpi, some rounding is often applied so that a logical pixel is an integer amount of actual pixels. Doing so avoids render artifacts. The final "pixel" obtained after these two steps becomes the "anchor" to which all other absolute measurements (e.g. the "centimeter") are based on.
Worked example, with a 2160p TV placed away from the viewer:
* Calculate the scaled pixel size as .
* Calculate the DPI of the TV as .
* Calculate the real-pixel count per logical-pixel as .
A browser will then choose to use the 1.721× pixel size, or round to a 2× ratio.
Megapixel
A megapixel (MP) is a million pixels; the term is used not only for the number of pixels in an image but also to express the number of image sensor
An image sensor or imager is a sensor that detects and conveys information used to make an image. It does so by converting the variable attenuation of light waves (as they pass through or reflect off objects) into signals, small bursts of curr ...
elements of digital camera
A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile device ...
s or the number of display elements of digital displays. For example, a camera that makes a 2048 × 1536 pixel image (3,145,728 finished image pixels) typically uses a few extra rows and columns of sensor elements and is commonly said to have "3.2 megapixels" or "3.4 megapixels", depending on whether the number reported is the "effective" or the "total" pixel count.
Pixel is used to define the resolution of a photo. Photo resolution is calculated by multiplying the width and height of a sensor in pixel.
Digital cameras use photosensitive electronics, either charge-coupled device
A charge-coupled device (CCD) is an integrated circuit containing an array of linked, or coupled, capacitors. Under the control of an external circuit, each capacitor can transfer its electric charge to a neighboring capacitor. CCD sensors are a ...
(CCD) or complementary metal–oxide–semiconductor
Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFE ...
(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
A Bayer filter mosaic is a color filter array (CFA) for arranging RGB color filters on a square grid of photosensors. Its particular arrangement of color filters is used in most single-chip digital image sensors used in digital cameras, camco ...
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 A demosaicing (also de-mosaicing, demosaicking or debayering) algorithm is a digital image process used to reconstruct a full color image from the incomplete color samples output from an image sensor overlaid with a color filter array (CFA). It is ...
, to create the final image. These sensor elements are often called "pixels", even though they only record one 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).
DxO Labs
DxO is a French company dedicated to photography. Founded in 2006, it is located in Boulogne-Billancourt.
It markets DxO PhotoLab, ViewPoint, and FilmPack image processing software and a connected camera, the DxO ONE.
History
DxO created DxOMar ...
invented the Perceptual MegaPixel
The Perceptual MegaPixel (P-MP) is a proprietary ranking of lens-camera combinations, created by DxO Labs. It is intended to express the resolution of which a combination of camera and lens is capable. Complete scientific or technical documentati ...
(P-MPix) to measure the sharpness that a camera produces when paired to a particular lens – as opposed to the MP a manufacturer states for a camera product, which is based only on the camera's sensor. The new P-MPix claims to be a more accurate and relevant value for photographers to consider when weighing up camera sharpness. As of mid-2013, the Sigma 35 mm f/1.4 DG HSM lens mounted on a Nikon D800
The Nikon D800 is a 36.3-megapixel professional-grade full-frame digital single-lens reflex camera produced by Nikon Corporation. It was given a Gold Award by Digital Photography Review.
It was officially announced on February 7, 2012 and went o ...
has the highest measured P-MPix. However, with a value of 23 MP, it still wipes off more than one-third of the D800's 36.3 MP sensor. In August 2019, Xiaomi released the Redmi Note 8 Pro as the world's first smartphone
A smartphone is a portable computer device that combines mobile telephone and computing functions into one unit. They are distinguished from feature phones by their stronger hardware capabilities and extensive mobile operating systems, whic ...
with 64 MP camera. On December 12, 2019 Samsung released Samsung A71 that also has a 64 MP camera. In late 2019, Xiaomi announced the first camera phone with 108 MP 1/1.33-inch across sensor. The sensor is larger than most of bridge camera
Bridge cameras are cameras that fill the niche between relatively simple point-and-shoot cameras and interchangeable-lens cameras such as mirrorless cameras and single-lens reflex cameras (SLRs). They are often comparable in size and weight ...
with 1/2.3-inch across sensor.
One new method to add megapixels has been introduced in a Micro Four Thirds System camera, which only uses a 16 MP sensor but can produce a 64 MP RAW (40 MP JPEG) image by making two exposures, shifting the sensor by a half pixel between them. Using a tripod to take level multi-shots within an instance, the multiple 16 MP images are then generated into a unified 64 MP image.
See also
* Computer display standard
Computer display standards are a combination of aspect ratio, display size, display resolution, color depth, and refresh rate. They are associated with specific expansion cards, video connectors and monitors.
History
Various computer display ...
* Dexel
The term ''Dexel'' has two common uses:
Dexel ("depth pixel") is a concept used for a discretized representation of functions defined on surfaces used in geometrical modeling and physical simulation, sometimes also referred to as multilevel Z-map. ...
* Gigapixel image
A gigapixel image is a digital image bitmap composed of one billion (109) pixels (picture elements), 1000 times the information captured by a 1 megapixel digital camera. A square image of 31,623 pixels in width and height is one gigapixel. Cu ...
* Image resolution
Image resolution is the detail an image holds. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail.
Image resolution can be measured in various ways. Resolution quantifies how ...
* Intrapixel and Interpixel processing
* LCD crosstalk
LCD crosstalk is a visual defect in an LCD screen which occurs because of interference between adjacent pixels.
Owing to the way rows and columns in the display are addressed, and charge is pushed around, the data on one part of the display has ...
* PenTile matrix family PenTile matrix is a family of patented subpixel matrix schemes used in electronic device displays. PenTile is a trademark of Samsung. PenTile matrices are used in AMOLED and LCD displays.
These subpixel layouts are specifically designed to operat ...
* Pixel advertising
The Million Dollar Homepage is a website conceived in 2005 by Alex Tew, a student from Wiltshire, England, to raise money for his university education. The home page consists of a million pixels arranged in a pixel grid; the image-based l ...
* Pixel art
Pixel art () is a form of digital art drawn with graphics software, 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 a ...
* Pixel art scaling algorithms
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 sm ...
* Pixel aspect ratio
Pixel aspect ratio (often abbreviated PAR) is a mathematical ratio that describes how the width of a pixel in a digital image compares to the height of that pixel.
Most digital imaging systems display an image as a grid of tiny, square pixe ...
* Pixelation
In computer graphics, pixelation (or pixellation in British English) is caused by displaying a bitmap or a section of a bitmap at such a large size that individual pixels, small single-colored square display elements that comprise the bitmap, a ...
* 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 Image resolution, resolution. It is primarily u ...
* Point (typography)
In typography, the point is the smallest unit of measure. It is used for measuring font size, leading, and other items on a printed page. The size of the point has varied throughout printing's history. Since the 18th century, the size of a poi ...
* Glossary of video terms
This glossary defines terms that are used in the documen"Defining Video Quality Requirements: A Guide for Public Safety" developed by thVideo Quality in Public Safety (VQIPS) Working Group It contains terminology and explanations of concepts relev ...
* Voxel
In 3D computer graphics, a voxel represents a value on a regular grid in three-dimensional space. As with pixels in a 2D bitmap, voxels themselves do not typically have their position (i.e. coordinates) explicitly encoded with their values. Ins ...
References
External links
A Pixel Is Not A Little Square
Microsoft Memo by computer graphics pioneer Alvy Ray Smith.
"Pixels and Me"
2016 lecture by Richard F. Lyon at the Computer History Museum
The Computer History Museum (CHM) is a museum of computer history, located in Mountain View, California. The museum presents stories and artifacts of Silicon Valley and the information age, and explores the computing revolution and its impact on ...
Square and non-Square Pixels
Technical info on pixel aspect ratios of modern video standards (480i, 576i, 1080i, 720p), plus software implications.
How a TV Works in Slow Motion - The Slow Mo Guys
– YouTube
YouTube is a global online video platform, online video sharing and social media, social media platform headquartered in San Bruno, California. It was launched on February 14, 2005, by Steve Chen, Chad Hurley, and Jawed Karim. It is owned by ...
video by The Slow Mo Guys
''The Slow Mo Guys'' is a science and technology entertainment web series from Thame, England, United Kingdom created by Gavin Free, starring himself and Daniel Gruchy. It has been described as the biggest channel for slow motion videos on YouTub ...
{{Photography
Computer graphics data structures
Digital geometry
Digital imaging
Digital photography
Display technology
Image processing
Television technology