
A pixel (a portmanteau of picture element) is one of the many tiny dots that make up the representation of a picture in a computer's memory. Usually the dots are so small and so numerous that, when printed on paper or displayed on a computer monitor, they appear to merge into a smooth image. The colour and intensity of each dot is chosen individually by the computer to represent a small area of the picture. Pixel is sometimes abbreviated px or pel (for "picture element"), although pel sometimes refers to ''#Sub-pixels''. ==Technical== Pixels are generally thought of as the smallest complete element of an image. The definition is highly context sensitive. For example, we can speak of pixels in a visible image (e.g. a printed page) or pixels carried by one or more electronic signal(s), or represented by one or more digital value(s), or pixels on a display device. This list is not exhaustive and depending on context there are several synonyms which are accurate in particular contexts, e.g. pel, sample, bytes, bits, dots, spots, superset, triad, stripe set, window, etc. We can also speak of pixels in the abstract, in particular when using pixels as a measure of resolution, e.g. 2400 pixels per inch or 640 pixels per line. Dots is often used to mean pixels, especially by computer sales and marketing people, and gives rise to the abbreviation DPI or dots per inch. Note that a pixel may be comprised of smaller parts known as sub-pixels. For example a pixel on a color display may be composed of red, green and blue sub-parts (sub-pixels, sub-pels, etc.) the three of which may be referred to as a triad. The terms "pixel" and "image element" are often used interchangeably, although this is technically incorrect. Image elements is a broader term than pixels and is also highly context sensitive. Image elements includes both complete pixels as well as those various sub-parts of pixels and other elements of images which are not pixel related such as DCT coefficients. For example, it is correct to say that the red part of an RGB pixel is an image element but it is not normally considered correct to refer to the red part as a pixel itself (although persons who are not skilled in the television industry often do). [[Image:Pixel-example.PNG|right|frame|This example shows a former Wikipedia logo with a portion greatly enlarged. The different shades of grey blend together to create the optical illusion of a smooth image. Note that sometimes (as in the example here) the edge pixels of text are reduced in shade to produce a less stepped look when viewed at normal size. This is called anti-aliasing.]] The more pixels used to represent an image, the closer the result will resemble the original. The number of pixels in an image is called the image resolution. This 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. The coloured dots that form a digitized image (such as a JPG file used on a web page) are also called pixels. Depending on how a computer displays an image, these may not be in one-to-one correspondence with screen pixels. In areas where the distinction is important, the dots in the image file may be called texels. In computer programming, an image composed of pixels is known as a ''bitmap'' or a ''raster graphics''. The word ''raster'' originates from analogue television technology. Bitmapped images are used to encode digital video and to produce computer-generated art. === Native vs. logical pixels === Since the resolution of most computer displays can be adjusted from the computer's operating system, a pixel is a purely relative measurement. Modern LCD computer displays are designed with a ''native resolution'' which refers to the perfect match between pixels and Triad (computers). (CRT displays also use red-green-blue phosphor triads, but these are not coincident with image pixels, and cannot therefore be said to be equivalent to pixels.) The native resolution will produce the sharpest picture capable from the display. However since the user can adjust the resolution, the monitor must be capable of displaying the resolution. Non-native resolutions have to be approximated by the software in the LCD screen, using interpolation algorithms. This often causes the screen to look jagged and blurry. For example, a display with a native resolution of 1280×1024 will look best set at 1280×1024 resolution, will display 800×600 adequately by drawing each pixel with more physical triads, and will be unable to display in 1600×1200 at all due to the lack of physical triads. Pixels can be either rectangular or square. A number called the ''aspect ratio'' describes the squareness of a pixel. For example, a 1.25:1 aspect ratio means that each pixel is 1.25 times wider than it is high. Pixels on computer monitors are usually square, but pixels used in digital video have non-square aspect ratios, such those used in the PAL and NTSC variants of the CCIR 601 digital video standard, and the corresponding anamorphic widescreen formats. Each pixel in a monochrome image has its own brightness. Zero usually represents black, and the maximum value possible represents white. For example, in an eight-bit image, the maximum unsigned value that can be stored by eight bits is 255, so this is the value used for white. In a colour image, each pixel has its own hue, saturation and value, usually represented as three numbers representing red, green and blue intensities respectively (see RGB). === Bits per pixel === The number of distinct colours that can be represented by a pixel depends on the number of bits per pixel (BPP). Common values are * 8 bpp (256 colours), * 16 bpp (65,536 colours, known as Highcolour), * 24 bpp (16,777,216 colours, known as Truecolour). Images composed of 256 colours or fewer are usually stored in the computer's video memory in chunky or planar format, where a pixel in memory is an index into a list of colours called a palette. These modes are therefore sometimes called ''indexed'' modes. While only 256 colours are displayed at once, those 256 colours are picked from a much larger palette, typically of 16 million colours. Changing the values in the palette permits a kind of animation effect. The animated startup logo of Windows 95 and Windows 98 is probably the best-known example of this kind of animation. For depths larger than 8 bits, the number is the total of the three RGB (red, green and blue) components. A 16-bit depth is usually divided into five bits for each of red and blue, and six bits for green (the eye being more sensitive to green). 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. On older systems, 4 bpp (16 colours) is also common. When an image file is displayed on a screen, the number of bits per pixel is expressed separately for the raster file and for the display. Some raster image file formats have a greater bit-depth capability than others. The GIF format, for example, has a maximum depth of 8 bits, while TIFF files can handle 48-bit pixels. There are no displays that can display 48 bits of colour, so this depth is typically used for specialized professional applications with film scanners and computer printers. Such files are rendering (computer graphics) on a screen with 24-bit depth. === Sub-pixels === Many display and image-acquisition systems are, for various reasons, not capable of displaying the different colour channels at the same site. This approach is generally resolved by using multiple sub-pixels, each of which handles a single colour channel. For example, LCD displays typically divide each pixel horizontally into three sub-pixels. Most LED displays divide each pixel into four sub-pixels; one red, one green, and two blue. Most digital camera sensors also use sub-pixels, by using coloured filters. (CRT displays also use red-green-blue phosphor dots, but these are not aligned with image pixels, and cannot therefore be said to be sub-pixels.) For systems with subpixels, two different approaches can be taken: * ignore the fact that the sub-pixels exist, and treat the system as if it used uniform pixels * take the sub-pixels into account, complicating the analysis, but potentially producing better images An example of a technology that uses the latter approach is the use of colour fringing on computer fonts to encode sub-pixel resolution luminance information. A recent technique for increasing the apparent resolution of a colour display, named subpixel rendering, uses knowledge of pixel geometry to manipulate the three coloured sub-pixels separately, which seems to be most effective with LCD displays set at native resolution. This is a form of anti-aliasing, and is mostly used to improve the appearance of text. Microsoft's ClearType, which is available in Windows XP, is an example of this. ==Megapixel== A megapixel is 1 million pixels, and is usually used to express the resolution capabilities of digital cameras. For example, a camera that can take pictures with a resolution of 2048×1536 pixels is commonly said to have "3.1 megapixels" (2048 × 1536 = 3,145,728). Some digital cameras (digicams) use Charge-coupled devices, which record brightness levels. Older digital cameras that do not use Foveon X3 CCDs have red, green, and blue colour filters so that each pixel can record the brightness of a single primary colour. Thus, the pixels of digital cameras that don't use Foveon X3 CCDs are similar to sub-pixels. The camera interpolates the colour information to create the final image. Thus, an 'x'-megapixel image from a digital camera can have as little as 1/4th the colour resolution of the same image as taken by a scanner. The detail resolution is unimpaired. Thus, a picture of a blue or red object will tend to look fuzzy compared to the same object in shades of grey. Green objects appear less fuzzy, since green is allocated more pixels (due to the eye's increased sensitivity for green). See [http://megamyth.homestead.com/imageres.html] for a more detailed discussion. == Similar concepts == Several other types of objects derived from the idea of the pixel, such as the voxel (volume element), texel (graphics) (texture element) and surfel (surface element), have been created for other computer graphics and image processing uses. ==See also== *Computer display standard *Image resolution *voxel *Vector graphics *hunt-the-pixel *putpixel *Map#Electronic maps *Pixel art *Gigapixel image ==External links== * [http://www.uwasa.fi/~f76998/video/conversion/ A Quick Guide to Digital Video Resolution and Pixel Aspect Ratios] Computer graphics Computing Image processing Display technology Computing portmanteaus
and in english this all means??? User:Jtdirl 16:16 May 6, 2003 (UTC) : Indeed. I've had a go at a clearer intro, but I'm not happy with it. I hope someone else can improve it. The problem is that it's very hard to say what a pixel is: screen element; printing; part of a digital image. Though in the last case we're strictly dealing with ''texels''; but only the 3D gaming industry makes that distinction AFAIK -- User:Tarquin 16:30 May 6, 2003 (UTC) I'm a historian whole technical skills are such that if I change a light bulb I am likely to black out all of North Dublin, so I am afraid the article went completely over my head, but then anything technical does anyway. But then I suppose people people are are technologically literate might find the stuff I write on historiography or royal naming procedures over ''their'' heads too. Each to his or her own! I notice BTW that an earlier version mentioned a mac's 'thousands' and 'millions' in term of screen colours, so I learned something about what that actually means on my eMac. Except that that info was culled from later versions!!! I decided to check just what the hell pixel was because I bought a new digital camera that uses 3.2 million pixels so I was hoping to find out what it was I had bought. The joys of being technologically illiterate! User:Jtdirl 19:44 May 6, 2003 (UTC) ---- Very nice picture, Tarquin! I'm even willing to overlook the fact that the lines connect the wrong corners. ;) -- User:JohnOwens 21:41 May 6, 2003 (UTC) : dang! I'll fix it later. -- User:Tarquin (boy am I glad I always keep my layered photoshop documents!) --------- I'm a bit put off by: ''" This can be expressed as a single total,"'', because it seems to me the single number is a product, not a total... but I can't see how to change it without making it too complicated -- User:Tarquin 21:48 May 6, 2003 (UTC) : Is this the bit that now reads ''"For depths larger than 8 bits, the number is the total of the three RGB ..."''? If so, I agree that total is the wrong word, but describing it in a way that a non computer-literate person will immediately grasp is difficult. Perhaps something along the lines of ''"For depths larger than 8 bits, the bits themselves are divided into three seperate values that describe the intensities of the red, green, and blue components of the desired colour."'', since the values are not really either a product or total. User:Lumpbucket 01:08 August 12, 2003 (BST) ---- I added a section on what a digital camera "megapixel" REALLY is, and also added sections for pels and sub-pixels. On the digicam megapixel subject, I sent an email to the apparent author of http://megamyth.homestead.com, asking him to contribute to the subject. User:Scott McNay 07:45, 2004 Feb 8 (UTC) ---- On another subject, can someone clarify several issues? I'd like to know: * whether a "dot pitch" is the same as the pixel size, as loudly implied by this article, and not clarified at all by the dot pitch article? * how "native resolution" (often seen in relation to LCDs) relates. * whether "native resolution" applies to CRTs or not (which is implied by this article in the sub-pixel section), at least for horizontal resolution. * How CRTs and LCDs display different horizontal resolutions when they have embedded color masks, and ditto for vertical resolution for LCDs. User:Scott McNay 07:45, 2004 Feb 8 (UTC) ---- Ok, looks like everything's been explained, and it all makes sense to me now; just have to clean up a bit now. User:Scott McNay 01:30, 2004 Feb 14 (UTC) ---- To do: * Find or make a picture showing how sub-pixel font rendering (SPFR) helps. Put it on appropriate page * Add mention on appropriate page of Apple (?) using SPFR on Apple II (?) * Factor Pixel page so that image pixels are discussed separately from monitor pixels, ec. Right now, kinda mixed up. * Find or make a picture showing pixel geometry for a typical digital camera. Mention that a digicam triad is quite large, due to having more green pixels than red or blue pixels. May want to un-redirect megapixel page. * Clarify that pixels and sub-pixels are logical constructs, and triads and dots are physical constructs. * Can someone clarify that SPFR really requires that the SPFR routine know the LCD monitor's native resolution, and/or works best when monitor is set to native resolution? * Can someone explain how SPFR works on CRTs (see Apple II reference), when the image's location on the screen can vary from moment to moment? User:Scott McNay 02:29, 2004 Feb 14 (UTC) ---- More info about SPFR available at http://www.grc.com/cleartype.htm * Considering that apparently some monitors (CRTs?) have vertical stripes, that would imply that diagonal dot pitch measurement simply doesn't apply to them, since verical resolution would be limited only by the number of scan lines that can be squeezed onto the screen. Comment? * Update pixel geometry to mention triads instead of pixels * Merge triad and pixel geometry pages? Could edit/replace pictures to show both the geometry and the outline of a triad on the pictures * Update triad to clarify that sub-pixel is not the same as a triad User:Scott McNay 03:01, 2004 Feb 14 (UTC) ---- As i have always known and was taught, dot pitch IS a diagonal measurement. It is the measurement of the shortest distance between 2 like-colored phosphor dots (what someone started terming sub-pixel). Since a triad is made up of the 3 color dots in a triangle formation, as they are placed on the screen the measurement of dot pitch is always diagonal. Dot pitch simply doesnt apply to an LCD screen, since LCD does not use phosphor dots, but rather a square made up of 3 tall rectangles in the primary colors. Sorry i do not know the term for that element in an LCD screen. Im sure someone can clarify it more in the article. : User:Enos Shenk 22:37, 14 Feb 2004 (UTC) ---- Does dot pich apply to Trinitron tubes? They have stripes also, I believe, and I don't have one to look at, but I would guess that the stripes are solid, not broken, meaning no vertical component. So now the question is, are some companies actually reporting incorrect values for dot pitch? The first link below has some discussion on the subject. * http://www.pctechguide.com/06crtmon.htm (starting with the dot pitch section) * http://www.pctechguide.com/07panels.htm * http://entertainment.howstuffworks.com/tv.htm * http://computer.howstuffworks.com/monitor.htm (see page monitor4) * http://computer.howstuffworks.com/question401.htm (none of the links at the end of the article are good) Add note that SPFR is sometimes called "pixel borrowing". After reading Wiki, HSW seems, well, mildly biased and incredulous. :) ---- (Forgot to put my sig above.) Ok, I will edit (unless someone else does it first; I have some cleaning up to do around here, and headed out for a few hours with a friend this afternoon) the various articles to indicate: * CRTs are analog and LCDs are digital, in the sense that on an LCD, a specific pixel can be guaranteed to correspond to a triad, whereas on CRTs, a pixel is most likely to land on varying parts of two triads (a pic showing this would be nice). Would it be accurate to say "Because of this vagueness, "native resolution" does not apply well to CRTs"? * "sub-pixel" refers to digital displays * "phosphor dot" refers to analog displays * stripe pitch (sometimes called dot pitch) is a horizontal measurement for Trinitron CRTs * dot pitch is a diagonal measurement for non-Trinitron CRT screens. For non-digital displays, the term is rather vague. * SPFR only applies to digital displays * SPFR seems to help on analog displays because it is an anti-alising method but standard methods give beter results for non-digital displays. * Add an image for slotted mask. [http://www.pctechguide.com/06crtmon.htm] shows the dot pitch being measured horizonally in this case, which I think is likely part of the cause of the "some companies measure wrong" issue. * Incorporate other dot pitch caveats from [http://www.pctechguide.com/06crtmon.htm]. * Etc. Is someone else here better than I am with making pictures? I just have MS Paint, here... User:Scott McNay 17:47, 2004 Feb 15 (UTC) ==New Pixel/new article== I'm starting the new article at Pixel/new. The idea about tiles in mosaic came from User:Fuzheado. User:Scott McNay 06:16, 2004 Feb 18 (UTC) == Difference between px, pt, em == Is there an article which covers the difference between px, Point (typography), and Em (typography) measurements? These are used in drawing programs, css, etc. A single article that ties them all together would be nice. (also pica, ex, etc.) css definitions: http://css.weblogsinc.com/entry/1234000933032102/ SVG definitions: http://www.xml.com/pub/a/2001/03/21/svg.html (what i was specifically looking for) how it relates to font size in pt, how it relates to DPI, etc., etc. - User:Omegatron 16:26, Apr 6, 2005 (UTC) == Rollback == I meant to edit a local version of this page, but instead edited the Wikipedia version. Is there a way to rollback to the previous version? == This article needs a lot of work == This article contains a large amount of pseudo-erudition caused by layer on layer of pedantic corrections. Some of the pedants knew something about image processing. Unfortunately, most didn't. It now desperately needs editing by actual image-processing experts, followed by extensive copyediting to remove redundancy and simplify flow. -- User:Karada 20:18, 22 Jun 2005 (UTC)
Pixel is Eric Vitiello's alter ego. Eric is a freelance Web Developer, located in Louisville, KY USA. ---- — Stevie_is_the_man!">User:Stevietheman Talk">User talk:Stevietheman | Contrib">Special:Contributions/Stevietheman 20:55, 12 Mar 2005 (UTC)
See other meanings of words starting from letter:
Words begining with Pixel:
Pixel
Pixel
Pixel
Pixel/new
Pixel23
Pixel32
Pixelart
Pixelati
Pixelation
Pixelati_Ltd.
Pixelati_Media
Pixelbox
Pixelfire
Pixelfire
Pixelization
Pixellation
Pixelmap
Pixelpalace3
Pixels
Pixelsheep
Pixelsurgeon
Pixels_per_inch
Pixels_per_inch
Pixeltarian
Pixeltoo
Pixeltoo
Pixelverde
Pixelverde
Pixelvision
Pixel_and_vertex_shaders
Pixel_Art
Pixel_art
Pixel_art
Pixel_artist
Pixel_display_format
Pixel_geometry
Pixel_hunt
Pixel_Perfect
Pixel_Pop
Pixel_shader
Pixel_shaders
Pixel
A pixel (a portmanteau of picture element) is one of the many tiny dots that make up the representation of a picture in a computer's memory. Usually the dots are so small and so numerous that, when printed on paper or displayed on a computer monitor, they appear to merge into a smooth image. The colour and intensity of each dot is chosen individually by the computer to represent a small area of the picture. Pixel is sometimes abbreviated px or pel (for "picture element"), although pel sometimes refers to ''#Sub-pixels''. ==Technical== Pixels are generally thought of as the smallest complete element of an image. The definition is highly context sensitive. For example, we can speak of pixels in a visible image (e.g. a printed page) or pixels carried by one or more electronic signal(s), or represented by one or more digital value(s), or pixels on a display device. This list is not exhaustive and depending on context there are several synonyms which are accurate in particular contexts, e.g. pel, sample, bytes, bits, dots, spots, superset, triad, stripe set, window, etc. We can also speak of pixels in the abstract, in particular when using pixels as a measure of resolution, e.g. 2400 pixels per inch or 640 pixels per line. Dots is often used to mean pixels, especially by computer sales and marketing people, and gives rise to the abbreviation DPI or dots per inch. Note that a pixel may be comprised of smaller parts known as sub-pixels. For example a pixel on a color display may be composed of red, green and blue sub-parts (sub-pixels, sub-pels, etc.) the three of which may be referred to as a triad. The terms "pixel" and "image element" are often used interchangeably, although this is technically incorrect. Image elements is a broader term than pixels and is also highly context sensitive. Image elements includes both complete pixels as well as those various sub-parts of pixels and other elements of images which are not pixel related such as DCT coefficients. For example, it is correct to say that the red part of an RGB pixel is an image element but it is not normally considered correct to refer to the red part as a pixel itself (although persons who are not skilled in the television industry often do). [[Image:Pixel-example.PNG|right|frame|This example shows a former Wikipedia logo with a portion greatly enlarged. The different shades of grey blend together to create the optical illusion of a smooth image. Note that sometimes (as in the example here) the edge pixels of text are reduced in shade to produce a less stepped look when viewed at normal size. This is called anti-aliasing.]] The more pixels used to represent an image, the closer the result will resemble the original. The number of pixels in an image is called the image resolution. This 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. The coloured dots that form a digitized image (such as a JPG file used on a web page) are also called pixels. Depending on how a computer displays an image, these may not be in one-to-one correspondence with screen pixels. In areas where the distinction is important, the dots in the image file may be called texels. In computer programming, an image composed of pixels is known as a ''bitmap'' or a ''raster graphics''. The word ''raster'' originates from analogue television technology. Bitmapped images are used to encode digital video and to produce computer-generated art. === Native vs. logical pixels === Since the resolution of most computer displays can be adjusted from the computer's operating system, a pixel is a purely relative measurement. Modern LCD computer displays are designed with a ''native resolution'' which refers to the perfect match between pixels and Triad (computers). (CRT displays also use red-green-blue phosphor triads, but these are not coincident with image pixels, and cannot therefore be said to be equivalent to pixels.) The native resolution will produce the sharpest picture capable from the display. However since the user can adjust the resolution, the monitor must be capable of displaying the resolution. Non-native resolutions have to be approximated by the software in the LCD screen, using interpolation algorithms. This often causes the screen to look jagged and blurry. For example, a display with a native resolution of 1280×1024 will look best set at 1280×1024 resolution, will display 800×600 adequately by drawing each pixel with more physical triads, and will be unable to display in 1600×1200 at all due to the lack of physical triads. Pixels can be either rectangular or square. A number called the ''aspect ratio'' describes the squareness of a pixel. For example, a 1.25:1 aspect ratio means that each pixel is 1.25 times wider than it is high. Pixels on computer monitors are usually square, but pixels used in digital video have non-square aspect ratios, such those used in the PAL and NTSC variants of the CCIR 601 digital video standard, and the corresponding anamorphic widescreen formats. Each pixel in a monochrome image has its own brightness. Zero usually represents black, and the maximum value possible represents white. For example, in an eight-bit image, the maximum unsigned value that can be stored by eight bits is 255, so this is the value used for white. In a colour image, each pixel has its own hue, saturation and value, usually represented as three numbers representing red, green and blue intensities respectively (see RGB). === Bits per pixel === The number of distinct colours that can be represented by a pixel depends on the number of bits per pixel (BPP). Common values are * 8 bpp (256 colours), * 16 bpp (65,536 colours, known as Highcolour), * 24 bpp (16,777,216 colours, known as Truecolour). Images composed of 256 colours or fewer are usually stored in the computer's video memory in chunky or planar format, where a pixel in memory is an index into a list of colours called a palette. These modes are therefore sometimes called ''indexed'' modes. While only 256 colours are displayed at once, those 256 colours are picked from a much larger palette, typically of 16 million colours. Changing the values in the palette permits a kind of animation effect. The animated startup logo of Windows 95 and Windows 98 is probably the best-known example of this kind of animation. For depths larger than 8 bits, the number is the total of the three RGB (red, green and blue) components. A 16-bit depth is usually divided into five bits for each of red and blue, and six bits for green (the eye being more sensitive to green). 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. On older systems, 4 bpp (16 colours) is also common. When an image file is displayed on a screen, the number of bits per pixel is expressed separately for the raster file and for the display. Some raster image file formats have a greater bit-depth capability than others. The GIF format, for example, has a maximum depth of 8 bits, while TIFF files can handle 48-bit pixels. There are no displays that can display 48 bits of colour, so this depth is typically used for specialized professional applications with film scanners and computer printers. Such files are rendering (computer graphics) on a screen with 24-bit depth. === Sub-pixels === Many display and image-acquisition systems are, for various reasons, not capable of displaying the different colour channels at the same site. This approach is generally resolved by using multiple sub-pixels, each of which handles a single colour channel. For example, LCD displays typically divide each pixel horizontally into three sub-pixels. Most LED displays divide each pixel into four sub-pixels; one red, one green, and two blue. Most digital camera sensors also use sub-pixels, by using coloured filters. (CRT displays also use red-green-blue phosphor dots, but these are not aligned with image pixels, and cannot therefore be said to be sub-pixels.) For systems with subpixels, two different approaches can be taken: * ignore the fact that the sub-pixels exist, and treat the system as if it used uniform pixels * take the sub-pixels into account, complicating the analysis, but potentially producing better images An example of a technology that uses the latter approach is the use of colour fringing on computer fonts to encode sub-pixel resolution luminance information. A recent technique for increasing the apparent resolution of a colour display, named subpixel rendering, uses knowledge of pixel geometry to manipulate the three coloured sub-pixels separately, which seems to be most effective with LCD displays set at native resolution. This is a form of anti-aliasing, and is mostly used to improve the appearance of text. Microsoft's ClearType, which is available in Windows XP, is an example of this. ==Megapixel== A megapixel is 1 million pixels, and is usually used to express the resolution capabilities of digital cameras. For example, a camera that can take pictures with a resolution of 2048×1536 pixels is commonly said to have "3.1 megapixels" (2048 × 1536 = 3,145,728). Some digital cameras (digicams) use Charge-coupled devices, which record brightness levels. Older digital cameras that do not use Foveon X3 CCDs have red, green, and blue colour filters so that each pixel can record the brightness of a single primary colour. Thus, the pixels of digital cameras that don't use Foveon X3 CCDs are similar to sub-pixels. The camera interpolates the colour information to create the final image. Thus, an 'x'-megapixel image from a digital camera can have as little as 1/4th the colour resolution of the same image as taken by a scanner. The detail resolution is unimpaired. Thus, a picture of a blue or red object will tend to look fuzzy compared to the same object in shades of grey. Green objects appear less fuzzy, since green is allocated more pixels (due to the eye's increased sensitivity for green). See [http://megamyth.homestead.com/imageres.html] for a more detailed discussion. == Similar concepts == Several other types of objects derived from the idea of the pixel, such as the voxel (volume element), texel (graphics) (texture element) and surfel (surface element), have been created for other computer graphics and image processing uses. ==See also== *Computer display standard *Image resolution *voxel *Vector graphics *hunt-the-pixel *putpixel *Map#Electronic maps *Pixel art *Gigapixel image ==External links== * [http://www.uwasa.fi/~f76998/video/conversion/ A Quick Guide to Digital Video Resolution and Pixel Aspect Ratios] Computer graphics Computing Image processing Display technology Computing portmanteaus
Pixel
and in english this all means??? User:Jtdirl 16:16 May 6, 2003 (UTC) : Indeed. I've had a go at a clearer intro, but I'm not happy with it. I hope someone else can improve it. The problem is that it's very hard to say what a pixel is: screen element; printing; part of a digital image. Though in the last case we're strictly dealing with ''texels''; but only the 3D gaming industry makes that distinction AFAIK -- User:Tarquin 16:30 May 6, 2003 (UTC) I'm a historian whole technical skills are such that if I change a light bulb I am likely to black out all of North Dublin, so I am afraid the article went completely over my head, but then anything technical does anyway. But then I suppose people people are are technologically literate might find the stuff I write on historiography or royal naming procedures over ''their'' heads too. Each to his or her own! I notice BTW that an earlier version mentioned a mac's 'thousands' and 'millions' in term of screen colours, so I learned something about what that actually means on my eMac. Except that that info was culled from later versions!!! I decided to check just what the hell pixel was because I bought a new digital camera that uses 3.2 million pixels so I was hoping to find out what it was I had bought. The joys of being technologically illiterate! User:Jtdirl 19:44 May 6, 2003 (UTC) ---- Very nice picture, Tarquin! I'm even willing to overlook the fact that the lines connect the wrong corners. ;) -- User:JohnOwens 21:41 May 6, 2003 (UTC) : dang! I'll fix it later. -- User:Tarquin (boy am I glad I always keep my layered photoshop documents!) --------- I'm a bit put off by: ''" This can be expressed as a single total,"'', because it seems to me the single number is a product, not a total... but I can't see how to change it without making it too complicated -- User:Tarquin 21:48 May 6, 2003 (UTC) : Is this the bit that now reads ''"For depths larger than 8 bits, the number is the total of the three RGB ..."''? If so, I agree that total is the wrong word, but describing it in a way that a non computer-literate person will immediately grasp is difficult. Perhaps something along the lines of ''"For depths larger than 8 bits, the bits themselves are divided into three seperate values that describe the intensities of the red, green, and blue components of the desired colour."'', since the values are not really either a product or total. User:Lumpbucket 01:08 August 12, 2003 (BST) ---- I added a section on what a digital camera "megapixel" REALLY is, and also added sections for pels and sub-pixels. On the digicam megapixel subject, I sent an email to the apparent author of http://megamyth.homestead.com, asking him to contribute to the subject. User:Scott McNay 07:45, 2004 Feb 8 (UTC) ---- On another subject, can someone clarify several issues? I'd like to know: * whether a "dot pitch" is the same as the pixel size, as loudly implied by this article, and not clarified at all by the dot pitch article? * how "native resolution" (often seen in relation to LCDs) relates. * whether "native resolution" applies to CRTs or not (which is implied by this article in the sub-pixel section), at least for horizontal resolution. * How CRTs and LCDs display different horizontal resolutions when they have embedded color masks, and ditto for vertical resolution for LCDs. User:Scott McNay 07:45, 2004 Feb 8 (UTC) ---- Ok, looks like everything's been explained, and it all makes sense to me now; just have to clean up a bit now. User:Scott McNay 01:30, 2004 Feb 14 (UTC) ---- To do: * Find or make a picture showing how sub-pixel font rendering (SPFR) helps. Put it on appropriate page * Add mention on appropriate page of Apple (?) using SPFR on Apple II (?) * Factor Pixel page so that image pixels are discussed separately from monitor pixels, ec. Right now, kinda mixed up. * Find or make a picture showing pixel geometry for a typical digital camera. Mention that a digicam triad is quite large, due to having more green pixels than red or blue pixels. May want to un-redirect megapixel page. * Clarify that pixels and sub-pixels are logical constructs, and triads and dots are physical constructs. * Can someone clarify that SPFR really requires that the SPFR routine know the LCD monitor's native resolution, and/or works best when monitor is set to native resolution? * Can someone explain how SPFR works on CRTs (see Apple II reference), when the image's location on the screen can vary from moment to moment? User:Scott McNay 02:29, 2004 Feb 14 (UTC) ---- More info about SPFR available at http://www.grc.com/cleartype.htm * Considering that apparently some monitors (CRTs?) have vertical stripes, that would imply that diagonal dot pitch measurement simply doesn't apply to them, since verical resolution would be limited only by the number of scan lines that can be squeezed onto the screen. Comment? * Update pixel geometry to mention triads instead of pixels * Merge triad and pixel geometry pages? Could edit/replace pictures to show both the geometry and the outline of a triad on the pictures * Update triad to clarify that sub-pixel is not the same as a triad User:Scott McNay 03:01, 2004 Feb 14 (UTC) ---- As i have always known and was taught, dot pitch IS a diagonal measurement. It is the measurement of the shortest distance between 2 like-colored phosphor dots (what someone started terming sub-pixel). Since a triad is made up of the 3 color dots in a triangle formation, as they are placed on the screen the measurement of dot pitch is always diagonal. Dot pitch simply doesnt apply to an LCD screen, since LCD does not use phosphor dots, but rather a square made up of 3 tall rectangles in the primary colors. Sorry i do not know the term for that element in an LCD screen. Im sure someone can clarify it more in the article. : User:Enos Shenk 22:37, 14 Feb 2004 (UTC) ---- Does dot pich apply to Trinitron tubes? They have stripes also, I believe, and I don't have one to look at, but I would guess that the stripes are solid, not broken, meaning no vertical component. So now the question is, are some companies actually reporting incorrect values for dot pitch? The first link below has some discussion on the subject. * http://www.pctechguide.com/06crtmon.htm (starting with the dot pitch section) * http://www.pctechguide.com/07panels.htm * http://entertainment.howstuffworks.com/tv.htm * http://computer.howstuffworks.com/monitor.htm (see page monitor4) * http://computer.howstuffworks.com/question401.htm (none of the links at the end of the article are good) Add note that SPFR is sometimes called "pixel borrowing". After reading Wiki, HSW seems, well, mildly biased and incredulous. :) ---- (Forgot to put my sig above.) Ok, I will edit (unless someone else does it first; I have some cleaning up to do around here, and headed out for a few hours with a friend this afternoon) the various articles to indicate: * CRTs are analog and LCDs are digital, in the sense that on an LCD, a specific pixel can be guaranteed to correspond to a triad, whereas on CRTs, a pixel is most likely to land on varying parts of two triads (a pic showing this would be nice). Would it be accurate to say "Because of this vagueness, "native resolution" does not apply well to CRTs"? * "sub-pixel" refers to digital displays * "phosphor dot" refers to analog displays * stripe pitch (sometimes called dot pitch) is a horizontal measurement for Trinitron CRTs * dot pitch is a diagonal measurement for non-Trinitron CRT screens. For non-digital displays, the term is rather vague. * SPFR only applies to digital displays * SPFR seems to help on analog displays because it is an anti-alising method but standard methods give beter results for non-digital displays. * Add an image for slotted mask. [http://www.pctechguide.com/06crtmon.htm] shows the dot pitch being measured horizonally in this case, which I think is likely part of the cause of the "some companies measure wrong" issue. * Incorporate other dot pitch caveats from [http://www.pctechguide.com/06crtmon.htm]. * Etc. Is someone else here better than I am with making pictures? I just have MS Paint, here... User:Scott McNay 17:47, 2004 Feb 15 (UTC) ==New Pixel/new article== I'm starting the new article at Pixel/new. The idea about tiles in mosaic came from User:Fuzheado. User:Scott McNay 06:16, 2004 Feb 18 (UTC) == Difference between px, pt, em == Is there an article which covers the difference between px, Point (typography), and Em (typography) measurements? These are used in drawing programs, css, etc. A single article that ties them all together would be nice. (also pica, ex, etc.) css definitions: http://css.weblogsinc.com/entry/1234000933032102/ SVG definitions: http://www.xml.com/pub/a/2001/03/21/svg.html (what i was specifically looking for) how it relates to font size in pt, how it relates to DPI, etc., etc. - User:Omegatron 16:26, Apr 6, 2005 (UTC) == Rollback == I meant to edit a local version of this page, but instead edited the Wikipedia version. Is there a way to rollback to the previous version? == This article needs a lot of work == This article contains a large amount of pseudo-erudition caused by layer on layer of pedantic corrections. Some of the pedants knew something about image processing. Unfortunately, most didn't. It now desperately needs editing by actual image-processing experts, followed by extensive copyediting to remove redundancy and simplify flow. -- User:Karada 20:18, 22 Jun 2005 (UTC)
Pixel
Pixel is Eric Vitiello's alter ego. Eric is a freelance Web Developer, located in Louisville, KY USA. ---- — Stevie_is_the_man!">User:Stevietheman Talk">User talk:Stevietheman | Contrib">Special:Contributions/Stevietheman 20:55, 12 Mar 2005 (UTC)
See other meanings of words starting from letter:
P
PA | PB | PC | PD | PE | PF | PG | PH | PI | PJ | PK | PL | PM | PN | PO | PR | PS | PT | PU | PW | PX | PY | PZ |Words begining with Pixel:
Pixel
Pixel
Pixel
Pixel/new
Pixel23
Pixel32
Pixelart
Pixelati
Pixelation
Pixelati_Ltd.
Pixelati_Media
Pixelbox
Pixelfire
Pixelfire
Pixelization
Pixellation
Pixelmap
Pixelpalace3
Pixels
Pixelsheep
Pixelsurgeon
Pixels_per_inch
Pixels_per_inch
Pixeltarian
Pixeltoo
Pixeltoo
Pixelverde
Pixelverde
Pixelvision
Pixel_and_vertex_shaders
Pixel_Art
Pixel_art
Pixel_art
Pixel_artist
Pixel_display_format
Pixel_geometry
Pixel_hunt
Pixel_Perfect
Pixel_Pop
Pixel_shader
Pixel_shaders
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YouTube.com videos better site than Turbo Tax 2007
