Pixel: Wikis

  
  
  
  

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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.
A photograph of sub-pixel display elements on a laptop's LCD screen
.In digital imaging, a pixel (or picture element[1]) is a single point in a raster image.The Pixel is the smallest addressable screen element, it is the smallest unit of picture which can be controlled.^ PIX [picture] EL ement) Generally, the smallest addressable unit on a display screen or bitmapped image.
  • Programmable Logic DesignLine : Design Resource for Automotive Engineering 21 January 2010 18:55 UTC www.pldesignline.com [Source type: General]
  • DSP DesignLine : Design Resource for Automotive Engineering 21 January 2010 18:55 UTC www.dspdesignline.com [Source type: General]
  • Mobile Handset DesignLine : Design Resource for Automotive Engineering 21 January 2010 18:55 UTC www.mobilehandsetdesignline.com [Source type: General]
  • EETimes Encyclopedia 21 January 2010 18:55 UTC www.eetimes.com [Source type: General]
  • TechOnline | TechOnline - Encyclopedia 21 January 2010 18:55 UTC www.techonline.com [Source type: Reference]

^ Pixel Resolutions These are the primary resolutions displayed on a PC. With more pixels on screen, more of the document is visible, but the text and images will appear smaller.
  • Programmable Logic DesignLine : Design Resource for Automotive Engineering 21 January 2010 18:55 UTC www.pldesignline.com [Source type: General]
  • DSP DesignLine : Design Resource for Automotive Engineering 21 January 2010 18:55 UTC www.dspdesignline.com [Source type: General]
  • Mobile Handset DesignLine : Design Resource for Automotive Engineering 21 January 2010 18:55 UTC www.mobilehandsetdesignline.com [Source type: General]
  • EETimes Encyclopedia 21 January 2010 18:55 UTC www.eetimes.com [Source type: General]
  • TechOnline | TechOnline - Encyclopedia 21 January 2010 18:55 UTC www.techonline.com [Source type: Reference]

^ A pixel may also be the smallest element of a light-sensitive device, such as cameras that use charge-coupled devices ( see CCD ).
  • pixel (electronics) -- Britannica Online Encyclopedia 21 January 2010 18:55 UTC www.britannica.com [Source type: Reference]

Each Pixel has its address. The address of Pixels corresponds to its coordinate. .Pixels are normally arranged in a 2-dimensional grid, and are often represented using dots or squares.^ Therefore, whole-pixel anti-aliasing does not represent a useful solution for improving small point-size type.
  • GRC | How Sub-Pixel Font Rendering Works   21 January 2010 18:55 UTC www.grc.com [Source type: FILTERED WITH BAYES]

^ Pixel Bender uses the data type, float, instead of the data type, Number, for representing real numbers.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.Each pixel is a sample of an original image, where more samples typically provide more-accurate representations of the original.^ The sample rate of this image is FWHM = 6 pixels.

^ Pixel Resolutions These are the primary resolutions displayed on a PC. With more pixels on screen, more of the document is visible, but the text and images will appear smaller.
  • Video/Imaging DesignLine : Design Resource for Automotive Engineering 21 January 2010 18:55 UTC www.videsignline.com [Source type: General]
  • EETimes Encyclopedia 21 January 2010 18:55 UTC www.eetimes.com [Source type: General]

^ In "Pixel Peeping Part II" I'll give you the full technical details on these images so we can see how accurate your peeping was!
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

The intensity of each pixel is variable. .In color image systems, a color is typically represented by three or four component intensities such as red, green, and blue, or cyan, magenta, yellow, and black.^ Such a new style display would indeed be a fabulous eBook component since it could display color images clearly while simultaneously employing sub-pixel rendering for its page's text.
  • GRC | How Sub-Pixel Font Rendering Works   21 January 2010 18:55 UTC www.grc.com [Source type: FILTERED WITH BAYES]

^ Returns a QImage in which the values of the red and blue components of all pixels have been swapped, effectively converting an RGB image to an BGR image.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In the premultiplied format the red, green, and blue channels are multiplied by the alpha component divided by 255.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.In some contexts (such as descriptions of camera sensors), the term pixel is used to refer to a single scalar element of a multi-component representation (more precisely called a photosite in the camera sensor context), while in others the term may refer to the entire set of such component intensities for a spatial position.^ A pixel may also be the smallest element of a light-sensitive device, such as cameras that use charge-coupled devices ( see CCD ).
  • pixel (electronics) -- Britannica Online Encyclopedia 21 January 2010 18:55 UTC www.britannica.com [Source type: Reference]

^ Use of Ink&Pixel’s Service constitutes acceptance and agreement to Ink&Pixel’s AUP as well as Ink&Pixel’s TOS (Terms of Service) .
  • Acceptable Use Policy | Ink&Pixel 21 January 2010 18:55 UTC www.inkandpixel.com [Source type: FILTERED WITH BAYES]

^ You cannot mix names from more than one set in the same reference.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.In color systems that use chroma subsampling, the multi-component concept of a pixel can become difficult to apply, since the intensity measures for the different color components correspond to different spatial areas in a such a representation.^ The LUT can be thought of as a table with 256 rows (one row for each pixel intensity) and 3 collumns (one collumn for each of the three primary colors, Red, Green and Blue).
  • Pixel Information page 21 January 2010 18:55 UTC www.nist.gov [Source type: FILTERED WITH BAYES]

^ Such a new style display would indeed be a fabulous eBook component since it could display color images clearly while simultaneously employing sub-pixel rendering for its page's text.
  • GRC | How Sub-Pixel Font Rendering Works   21 January 2010 18:55 UTC www.grc.com [Source type: FILTERED WITH BAYES]

^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.The word pixel is based on a contraction of pix ("pictures") and el (for "element"); similar formations with el  for "element" include the words: voxel[2] and texel.^ A single picture element (a "pixel") of an LCD screen is actually composed of three "sub-pixels": one red, one green, and one blue (R-G-B).
  • GRC | How Sub-Pixel Font Rendering Works   21 January 2010 18:55 UTC www.grc.com [Source type: FILTERED WITH BAYES]

[2]

Contents

Etymology

.The word "pixel" was first published in 1965 by Frederic C. Billingsley of JPL (in Pasadena, CA), to describe the picture elements of video images from space probes to the Moon and Mars.^ First, the gray level of the pixel in the foreground image is calculated by averaging the color channels.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Pixel Bender effects can be applied to any display object, including images, vector graphics, and even digital video.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Furthermore, in our algorithm, the images are “dragged” across each other in increments (probes) to then perform the pixel subtraction.
  • Pixel Vision 21 January 2010 18:55 UTC pixel-vision.net [Source type: FILTERED WITH BAYES]

However, Billingsley did not coin the term himself. .Instead, he got the word "pixel" from Keith E. McFarland, at the Link Division of General Precision in Palo Alto, who did not know where the word originated.^ Page rank boost This pixel ad script generates direct links to your advertiser's websites which your advertiser can use to boost their search engine rank.
  • Automated million pixel ad script for PayPal, Google Ad, PHP, MySql 21 January 2010 18:55 UTC milliondollarpixelscriptphp.com [Source type: FILTERED WITH BAYES]

McFarland said simply it was "in use at the time" (circa 1963).[3]
The word is a combination of picture and element, via pix. The word pix appeared in Variety magazine headlines in 1932, as an abbreviation for the word pictures, in reference to movies.[4] By 1938, "pix" was being used in reference to still pictures by photojournalists.[3]
.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.^ A single picture element (a "pixel") of an LCD screen is actually composed of three "sub-pixels": one red, one green, and one blue (R-G-B).
  • GRC | How Sub-Pixel Font Rendering Works   21 January 2010 18:55 UTC www.grc.com [Source type: FILTERED WITH BAYES]

According to various etymologies, the earliest publication of the term picture element itself was in Wireless World magazine in 1927,[5] though it had been used earlier in various U.S. patents filed as early as 1911.[6]
Some authors explain pixel as picture cell, as early as 1972.[7]
.In video processing, pel is often used instead of pixel.^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In the evaluatePixel() function, the pixel at the output coordinates currently being processed is accessed using two built-in functions, sampleNearest() and outCoord() .
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Pixel Bender uses the data type, float, instead of the data type, Number, for representing real numbers.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

[8] For example, IBM used it in their Technical Reference for the original PC.

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)
A voxel is a volume element, the 3D analogue of a 2D pixel.
.Surfels (surface elements) have the same naming pattern as pixels, but share more similarities with shrunken triangles than expanded pixels.^ You cannot mix names from more than one set in the same reference.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

Technical

.A pixel does not need to be rendered as a small square.^ No need for the buyer to re-fit her picture to her order's size --- this pixel ad script does it automatically for her.
  • Automated million pixel ad script for PayPal, Google Ad, PHP, MySql 21 January 2010 18:55 UTC milliondollarpixelscriptphp.com [Source type: FILTERED WITH BAYES]

^ At Pixel Chefs we’ll be there for you long after the last kilobyte has been uploaded, whether you need to make a small change or a total redesign.
  • Pixel Chefs Orlando Web Design 21 January 2010 18:55 UTC www.pixelchefs.com [Source type: General]

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 a digital image.^ Returns a QImage in which the values of the red and blue components of all pixels have been swapped, effectively converting an RGB image to an BGR image.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Pixel Bender effects can be applied to any display object, including images, vector graphics, and even digital video.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ The image depth is the number of bits used to encode a single pixel, also called bits per pixel (bpp).
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

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 (photosensor elements).^ Since the colorA and colorB parameters are of type pixel4, there are four values in the array, one for each channel in the pixel.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ You can customize, globally or on a per-page-basis at each pixel ad script page whether Google Adsense should be displayed.
  • Automated million pixel ad script for PayPal, Google Ad, PHP, MySql 21 January 2010 18:55 UTC milliondollarpixelscriptphp.com [Source type: FILTERED WITH BAYES]

^ Pixel Bender effects can be applied to any display object, including images, vector graphics, and even digital video.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

This list is not exhaustive, and depending on context, there are several terms that are synonymous in particular contexts, such as pel, sample, byte, bit, dot, spot, etc. .The term "pixels" can be used in the abstract, or as a unit of measure, in particular when using pixels as a measure of resolution, such as: 2400 pixels per inch, 640 pixels per line, or spaced 10 pixels apart.^ When applying a Pixel Bender shader as a bitmap filter using generic AS3 code in Flash 10, it looks something like this: .
  • Pixel Bender Integration - Flex SDK - Adobe Open Source 21 January 2010 18:55 UTC opensource.adobe.com [Source type: Reference]

^ The image is stored using 1-bit per pixel.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ For example, you could use the following sampling statement to sample the pixel that is 10 pixels right and 5 pixels down from the current pixel: .
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.The measures dots per inch (dpi) and pixels per inch (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.^ The image is stored using 1-bit per pixel.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Inverting an 8-bit image means to replace all pixels using color index i with a pixel using color index 255 minus i .
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The image depth is the number of bits used to encode a single pixel, also called bits per pixel (bpp).
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

ink droplet) placement.[9] For example, a high-quality photographic image may be printed with 600 ppi on a 1200 dpi inkjet printer.[10] .Even higher dpi numbers, such as the 4800 dpi quoted by printer manufacturers since 2002, do not mean much in terms of achievable resolution.^ The term float stands for floating-point (which just means that the decimal point can "float" to any position in the number).
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

[11]
.The more pixels used to represent an image, the closer the result can resemble the original.^ In the evaluatePixel() function, the pixel at the current coordinate is sampled in each image using the sampleNearest() function.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The offset () function returns the number of pixels by which the image is intended to be offset by when positioned relative to other images, which also can be manipulated using the setOffset () function.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.The number of pixels in an image is sometimes called the resolution, though resolution has a more specific definition.^ The offset () function returns the number of pixels by which the image is intended to be offset by when positioned relative to other images, which also can be manipulated using the setOffset () function.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The number of channels in the output image produced by the shader is determined by the data type of the output pixel, not by the data types of the inputs.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Returns the number of pixels by which the image is intended to be offset by when positioning relative to other images.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.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.^ To obtain a single entry, use the pixelIndex () function to retrieve the pixel index for a given pair of coordinates, then use the color () function to retrieve the color.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The image depth is the number of bits used to encode a single pixel, also called bits per pixel (bpp).
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Pixel Bender effects can be applied to any display object, including images, vector graphics, and even digital video.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.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.^ The functions used to manipulate an image's pixels depend on the image format.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ First, the gray level of the pixel in the foreground image is calculated by averaging the color channels.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ QImage is designed and optimized for I/O, and for direct pixel access and manipulation, while QPixmap is designed and optimized for showing images on screen.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

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.^ The Pixel Bender coordinate system is similar to that used by Flash Player and AIR. The origin is registered at the top, left corner.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

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.^ This example uses the same ActionScript code, except it is loading and applying a different shader.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ When using scalar values, the operation is applied to each channel.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Again, this example uses the same ActionScript code, but it loads and applies a different shader.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.Other arrangements of pixels are also possible, with some sampling patterns even changing the shape (or kernel) of each pixel across the image.^ In the evaluatePixel() function, the pixel at the current coordinate is sampled in each image using the sampleNearest() function.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Samples a pixel from the input image Applies a calculation to the sampled pixel color Assigns the modified value to the output pixel The following simple Pixel Bender kernel does each of these tasks.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ A Pixel Bender kernel is run once for every pixel in the output image.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.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.^ Use the convertToFormat () functions to convert an image into another format.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Returns a QImage in which the values of the red and blue components of all pixels have been swapped, effectively converting an RGB image to an BGR image.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Constructs an image with the given width , height and format , that uses an existing memory buffer, data .
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

For example:
.
  • Text rendered using Cleartype
    LCD screens typically use a staggered grid, where the red, green, and blue components are sampled at slightly different locations.^ Returns a QImage in which the values of the red and blue components of all pixels have been swapped, effectively converting an RGB image to an BGR image.
    • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

    ^ In the premultiplied format the red, green, and blue channels are multiplied by the alpha component divided by 255.
    • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

    ^ Unlike the sensors in most DSLRs, which use separate pixels to detect red, green and blue light, in a Foveon type sensor each pixel generates a red, green and blue signal.
    • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

    .Subpixel rendering 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.^ The functions used to manipulate an image's pixels depend on the image format.
    • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
    • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

    ^ Take a look at these two images.
    • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

    ^ Returns the color of the pixel at the given position .
    • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
    • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

    [12]
  • The use of non-uniform grids is an active research area, attempting to bypass the traditional Nyquist limit.[13]
  • Pixels on computer monitors are normally "square" (this is, having equal horizontal and vertical sampling pitch); pixels in other systems are often "rectangular" (that is, having unequal horizontal and vertical sampling pitch – oblong in shape), as are digital video formats with diverse aspect ratios, such as the anamorphic widescreen formats of the CCIR 601 digital video standard.

Display resolution vs. native resolution in computer monitors

.Computers can use pixels to display an image, often an abstract image that represents a GUI.^ In the evaluatePixel() function, the pixel at the current coordinate is sampled in each image using the sampleNearest() function.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The offset () function returns the number of pixels by which the image is intended to be offset by when positioned relative to other images, which also can be manipulated using the setOffset () function.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.The resolution of this image is called the display resolution and is determined by the video card of the computer.^ Pixel Bender effects can be applied to any display object, including images, vector graphics, and even digital video.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.LCD computer monitors also use pixels to display an image, and have a native resolution.^ In the evaluatePixel() function, the pixel at the current coordinate is sampled in each image using the sampleNearest() function.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The offset () function returns the number of pixels by which the image is intended to be offset by when positioned relative to other images, which also can be manipulated using the setOffset () function.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.Each pixel is made up of triads, with the number of these triads determining the native resolution.^ The number of channels in the output image produced by the shader is determined by the data type of the output pixel, not by the data types of the inputs.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Spice up your site with these super yummy mini-pixel icons!
  • ExplodingBoy Pixel Icons at ExplodingBoy 21 January 2010 18:55 UTC www.exploding-boy.com [Source type: General]

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 don't have a native resolution at all - instead they have a set of resolutions that are equally well supported.^ On most forums (see dpreview.com for an example) pixel peeping is practically all they do...
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

.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.^ If a filter kernel takes additional images as inputs, these must be set before the filter is assigned to a display object.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ My guess is; Image A was taken with a film camera and then scanned in at a resolution to match, as closely as possible, Image B which was taken with a digital camera.
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

.On a CRT with a fixed beam sweep rate, you are required to use the native resolution.^ You can declare more inputs than are required for the way a kernel is used in Flex.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ However, the way you use a kernel in Flex creates additional requirements on the number of inputs.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.On a CRT without this restriction, you may use any resolution supported by the monitor that matches the monitor's physical aspect ratio and it will look fine.^ You can find out if a specific image or format supports embedding text by using QImageWriter::supportsOption ().
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

If the aspect ratio of the physical display and the selected resolution are different, many different things can happen. .On some LCDs, the monitor will stretch or squash the image to fill the entire display.^ Fills the entire image with the given pixelValue .
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

This can result in the image appearing blurry or jagged.
.On others, the aspect ratio will be maintained while expanding the image to fit the display, resulting in black bars on the top or sides of the image.^ If aspectRatioMode is Qt::KeepAspectRatio , the image is scaled to a rectangle as large as possible inside size , preserving the aspect ratio.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ It does not change the scale or aspect ratio of the image when it is rendered on other paint devices.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Together with dotsPerMeterX (), this number defines the intended scale and aspect ratio of the image, and determines the scale at which QPainter will draw graphics on the image.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

This can also result in the image appearing blurry or jagged, depending on the native resolution of the display and the selected resolution on the computer. For example, let's take the relatively common case of a full-screen application written assuming a 4:3 aspect ratio running on a 16:10 aspect ratio widescreen display. .If the selected resolution were 1600×1200 and you were running it on a 1920×1200 display that maintains aspect ratio while expanding the image to fit, the image would not look blurry, because each pixel in the 1600×1200 image maps to exactly 1 pixel on the 1920×1200 display.^ If aspectRatioMode is Qt::KeepAspectRatio , the image is scaled to a rectangle as large as possible inside size , preserving the aspect ratio.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ You are no longer constrained with the standard look of a 1000x1000 pixel million dollar homepage.
  • Automated million pixel ad script for PayPal, Google Ad, PHP, MySql 21 January 2010 18:55 UTC milliondollarpixelscriptphp.com [Source type: FILTERED WITH BAYES]

^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

If the selected resolution were 1280×960, the display would have to try to stretch the 960 pixels to fill 1200 pixels, which would mean each of the selected resolution pixels needs to take up 1.25 pixels on the physical display. .Since this can't be done, the monitor uses some scheme to figure out how to distribute the colors from those 960 pixels to fill the 1200 pixels of the physical display.^ This enum type is used to describe how pixel values should be inverted in the invertPixels () function.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Inverting an 8-bit image means to replace all pixels using color index i with a pixel using color index 255 minus i .
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In case of a 32-bit image, the setPixel () function can be used to alter the color of the pixel at the given coordinates to any other color specified as an ARGB quadruplet.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

This mapping results in a blurry or jagged appearance. .However, if the selected resolution were 800×600, you would be OK again, because 600 pixels can be expanded to 1200 pixels by having each pixel from the selected resolution take up 2 pixels on the physical display.^ Because a shader object is cloned when you set the blendShader property of a display object, you cannot simply change the parameter value of the original Shader object.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ By clicking “Sign Up”, you agree to adhere to our Terms of Service Earn points when you share Pixel .
  • Play Pixel, a free online game on Kongregate 21 January 2010 18:55 UTC www.kongregate.com [Source type: FILTERED WITH BAYES]

^ You cannot use the uchar* pointer directly, because the pixel format depends on the byte order on the underlying platform.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.On yet other LCD monitors, if the selected resolution is less than the native resolution of the monitor, the monitor will display things in the selected resolution, with a black border around the edges.^ Agreed, the final boss may have been less strange if I could do anything other than just sit and shoot at him.
  • Pixel Walkthrough Guide, Review, Discussion, Hints and Tips at Jay is Games 21 January 2010 18:55 UTC jayisgames.com [Source type: General]

Bits per pixel

.The number of distinct colors that can be represented by a pixel depends on the number of bits per pixel (bpp).^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In case of a 8-bit and monchrome images, the pixel value is only an index from the image's color table.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Pixel Bender uses the data type, float, instead of the data type, Number, for representing real numbers.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.A 1 bpp image uses 1-bit for each pixel, so each pixel can be either on or off.^ The image is stored using 1-bit per pixel.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The reason is that monochrome and 8-bit images are index-based and use a color lookup table, while 32-bit images store ARGB values directly.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In the evaluatePixel() function, the pixel at the current coordinate is sampled in each image using the sampleNearest() function.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

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)
  • 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 ≈ 16.8 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.^ The color depth of the returned image is 8-bit.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Returns a QImage in which the values of the red and blue components of all pixels have been swapped, effectively converting an RGB image to an BGR image.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In the premultiplied format the red, green, and blue channels are multiplied by the alpha component divided by 255.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.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.^ Monochrome images are stored using 1-bit indexes into a color table with at most two colors.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In the premultiplied format the red, green, and blue channels are multiplied by the alpha component divided by 255.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Red channel: pix.r or pix[0] Green channel: pix.g or pix[1] Blue channel: pix.b or pix[2] Alpha channel: pix.a or pix[3] Red and alpha channels: pix.ra All the color channels with red and blue swapped and no alpha channel: pix.bgr A single color channel is a 32-bit floating-point number, normally between 0.0 (black) and 1.0 (white).
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.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.^ In the premultiplied format the red, green, and blue channels are multiplied by the alpha component divided by 255.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Red channel: pix.r or pix[0] Green channel: pix.g or pix[1] Blue channel: pix.b or pix[2] Alpha channel: pix.a or pix[3] Red and alpha channels: pix.ra All the color channels with red and blue swapped and no alpha channel: pix.bgr A single color channel is a 32-bit floating-point number, normally between 0.0 (black) and 1.0 (white).
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Returns the alpha channel of the image as a new grayscale QImage in which each pixel's red, green, and blue values are given the alpha value of the original image.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.A 24-bit depth allows 8 bits per component.^ The image depth is the number of bits used to encode a single pixel, also called bits per pixel (bpp).
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.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).^ The given invert mode only have a meaning when the image's depth is 32.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The color depth of the returned image is 8-bit.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The monochrome (1-bit), 8-bit and 32-bit images are available in all versions of Qt.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

Subpixels

Geometry of color elements of various CRT and LCD displays; phosphor dots in a color CRT display (top row) bear no relation to pixels or subpixels.
.Many display and image-acquisition systems are, for various reasons, not capable of displaying or sensing the different color channels at the same site.^ First, the gray level of the pixel in the foreground image is calculated by averaging the color channels.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ I will tell you that I'm not "cheating" and showing the same image with different post exposure processing.
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

^ The point in guessing is to show just how many different interpretations you can make - most of them reasonably consistant with observations - given the same data.
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

.Therefore, the pixel grid is divided into single-color regions that contribute to the displayed or sensed color when viewed at a distance.^ To obtain a single entry, use the pixelIndex () function to retrieve the pixel index for a given pair of coordinates, then use the color () function to retrieve the color.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ They are divided into four different color sets — blue, pale blue, orange, and grey.
  • ExplodingBoy Pixel Icons at ExplodingBoy 21 January 2010 18:55 UTC www.exploding-boy.com [Source type: General]

^ Easy picture and grid customization This pixel ad script provides sample pictures and grids so that you can just choose what you like to display on your website.
  • Automated million pixel ad script for PayPal, Google Ad, PHP, MySql 21 January 2010 18:55 UTC milliondollarpixelscriptphp.com [Source type: FILTERED WITH BAYES]

.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.^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Samples a pixel from the input image Applies a calculation to the sampled pixel color Assigns the modified value to the output pixel The following simple Pixel Bender kernel does each of these tasks.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ To obtain a single entry, use the pixelIndex () function to retrieve the pixel index for a given pair of coordinates, then use the color () function to retrieve the color.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

(When the square pixel is divided into three subpixels, each subpixel is necessarily rectangular. To make them less oblong, two subpixels per color are used, see pixels on an LCD TV.)
.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.^ Shaders used as filters are applied to a single image.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ The reason is that monochrome and 8-bit images are index-based and use a color lookup table, while 32-bit images store ARGB values directly.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In the evaluatePixel() function, the pixel at the current coordinate is sampled in each image using the sampleNearest() function.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

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, uses knowledge of pixel geometry to manipulate the three colored subpixels separately, producing a slight increase in the apparent resolution of color displays.^ The offset () function returns the number of pixels by which the image is intended to be offset by when positioned relative to other images, which also can be manipulated using the setOffset () function.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ When the image is used, the color table must be large enough to have entries for all the pixel/index values present in the image, otherwise the results are undefined.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Unlike the sensors in most DSLRs, which use separate pixels to detect red, green and blue light, in a Foveon type sensor each pixel generates a red, green and blue signal.
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

.While CRT displays also 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 currently use subpixel rendering.^ For example, the following statement swaps the red and green color channels of a pixel vector when assigning the pixel value to another variable: .
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ To use a kernel as an area fill, create a Shader object containing the kernel bytecode and pass that to the beginShaderFill() function of the display object graphics property when drawing the object.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ In the evaluatePixel() function, the pixel at the current coordinate is sampled in each image using the sampleNearest() function.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

Megapixel

.A megapixel (MP) 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.^ In case of a 8-bit and monchrome images, the pixel value is only an index from the image's color table.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ The offset () function returns the number of pixels by which the image is intended to be offset by when positioned relative to other images, which also can be manipulated using the setOffset () function.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ When the image is used, the color table must be large enough to have entries for all the pixel/index values present in the image, otherwise the results are undefined.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

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.^ I'll just add that these images were not shot with the same camera using different "in camera" settings either!
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

^ Although the top image is showing some horrible "artifacts", if I may use that word, (I am not quite up on all this digital jargon), I believe in real world picture taking this would produce sharper and more contrasty images.
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

^ This leads me to think that these images were taking using exactly the same camera (and at the same settings, as Bob already indicated).
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

[14]
.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.^ I'll just add that these images were not shot with the same camera using different "in camera" settings either!
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

^ The image depth is the number of bits used to encode a single pixel, also called bits per pixel (bpp).
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ My guess is; Image A was taken with a film camera and then scanned in at a resolution to match, as closely as possible, Image B which was taken with a digital camera.
  • Pixel Peeping Part 1 - photo.net 21 January 2010 18:55 UTC photo.net [Source type: General]

.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.^ In the premultiplied format the red, green, and blue channels are multiplied by the alpha component divided by 255.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Red channel: pix.r or pix[0] Green channel: pix.g or pix[1] Blue channel: pix.b or pix[2] Alpha channel: pix.a or pix[3] Red and alpha channels: pix.ra All the color channels with red and blue swapped and no alpha channel: pix.bgr A single color channel is a 32-bit floating-point number, normally between 0.0 (black) and 1.0 (white).
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ For vector types such as colors, the array contains an element for each element of the vector.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

.The camera interpolates the color information of neighboring sensor elements, through a process called demosaicing, to create the final image.^ Creates and returns a mask for this image based on the given color value.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ In case of monochrome and 8-bit images, the colorCount () and colorTable () functions provide information about the color components used to store the image data: The colorTable () function returns the image's entire color table.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Note that if you create an 8-bit image manually, you have to set a valid color table on the image as well.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.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.^ First, the gray level of the pixel in the foreground image is calculated by averaging the color channels.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Returns a QImage in which the values of the red and blue components of all pixels have been swapped, effectively converting an RGB image to an BGR image.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Notice that colorCount() returns 0 for 32-bpp images because these images do not use color tables, but instead encode pixel values as ARGB quadruplets.
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.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.^ Returns the size of the color table for the image.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ First, the gray level of the pixel in the foreground image is calculated by averaging the color channels.
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Monochrome images are stored using 1-bit indexes into a color table with at most two colors.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

.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).^ In the premultiplied format the red, green, and blue channels are multiplied by the alpha component divided by 255.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]
  • Qt 4.6: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

^ Red channel: pix.r or pix[0] Green channel: pix.g or pix[1] Blue channel: pix.b or pix[2] Alpha channel: pix.a or pix[3] Red and alpha channels: pix.ra All the color channels with red and blue swapped and no alpha channel: pix.bgr A single color channel is a 32-bit floating-point number, normally between 0.0 (black) and 1.0 (white).
  • Pixel Bender basics for Flex and AIR | Adobe Developer Connection 21 January 2010 18:55 UTC www.adobe.com [Source type: Reference]

^ Returns the alpha channel of the image as a new grayscale QImage in which each pixel's red, green, and blue values are given the alpha value of the original image.
  • Qt 4.5.3: QImage Class Reference 21 January 2010 18:55 UTC doc.trolltech.com [Source type: Reference]

Standard display resolutions

Display standards comparison
Selected standard display resolutions include:
Name Resolution
(megapixels)
Width x Height
CGA 0.064 320×200
EGA 0.224 640×350
VGA 0.3 640×480
SVGA 0.5 800×600
XGA 0.8 1024×768
SXGA 1.3 1280×1024
UXGA 1.9 1600×1200
WUXGA 2.3 1920×1200

See also

References

  1. ^ Rudolf F. Graf (1999). Modern Dictionary of Electronics. Oxford: Newnes. p. 569. ISBN 0-7506-43315. http://books.google.com/books?id=o2I1JWPpdusC&pg=PA569&dq=pixel+intitle:%22Modern+Dictionary+of+Electronics%22+inauthor:graf&lr=&as_brr=0&ei=5ygASM3qHoSgiwH45-GIDA&sig=7tg-LuGdu6Njypaawi2bbkeq8pw.  
  2. ^ a b Foley, James D.; Andries van Dam, John F. Hughes, Steven K. Feiner (1990). "Spatial-partitioning representations; Surface detail". Computer Graphics Principles and Practice. The Systems Programming Series. Addison-Wesley. ISBN 0-201-12110-7. "These cells are often called voxels (volume elements), in analogy to pixels."  
  3. ^ a b Lyon, Richard F. (2006). A brief history of 'pixel'. IS&T/SPIE Symposium on Electronic Imaging.
  4. ^ "Online Etymology Dictionary". http://www.etymonline.com/index.php?search=pixel.  
  5. ^ "On language; Modem, I'm Odem", The New York Times, April 2, 1995. Accessed April 7, 2008.
  6. ^ Sinding-Larsen, Alf Transmission of Pictures of Moving Objects, US Patent 1,175,313, issued March 14, 1916.
  7. ^ Robert L. Lillestrand (1972). "Techniques for Change Detection". IEEE Trans. Computers C-21 (7).  
  8. ^ Lewis, Peter H. (February 12, 1989). The Executive Computer; Compaq Sharpens Its Video Option. The New York Times.
  9. ^ Derek Doeffinger (2005). The Magic of Digital Printing. Lark Books. p. 24. ISBN 1579906893. http://books.google.com/books?id=s2hIx1amJUcC&pg=PA24&dq=printer+dots-per-inch+pixels-per-inch&ei=ilKfSKjyBYm6tQPAu9WdBQ&sig=ACfU3U1img9C-r3_16xNKoYjTubg02GyVA.  
  10. ^ "Experiments with Pixels Per Inch (PPI) on Printed Image Sharpness". ClarkVision.com. July 3, 2005. http://www.clarkvision.com/imagedetail/printer-ppi/.  
  11. ^ Harald Johnson (2002). Mastering Digital Printing. Thomson Course Technology. p. 40. ISBN 1929685653. http://books.google.com/books?id=wto19gxFyfQC&pg=PA40&dq=inkjet+printer+4800+dpi+addressability&lr=&as_brr=3&ei=ZI-kSITKAo3sswO7g-2dBQ&sig=ACfU3U2RdAVkFq_0rsmQK6QwKPcDveJcxg#PPA41,M1.  
  12. ^ "Image registration of blurred satellite images". http://staff.utia.cas.cz/zitova/registration.htm. Retrieved 2008-05-09.  
  13. ^ "ScienceDirect - Pattern Recognition: Image representation by a new optimal non-uniform morphological sampling:". http://www.sciencedirect.com/science/article/B6V14-3YXB1T5-8/2/15b559f2aefbc7bdc54c55df148c2374. Retrieved 2008-05-09.  
  14. ^ Michael Goesele (2004). New Acquisition Techniques for Real Objects and Light Sources in Computer Graphics. Books on Demand. ISBN 3833414898. http://books.google.com/books?id=ZTJJ8QzNv1wC&pg=PA33&dq=sensel+sensor-element&lr=&as_brr=0&ei=t_-4R7WMPKCQtwOV-I2SBQ&sig=nbPybOvZhWwQSt0uS0Rtq60mJlg.  

External links


Wiktionary

Up to date as of January 15, 2010

Definition from Wiktionary, a free dictionary

See also pixel

German

Noun

Pixel n. (genitive Pixels, plural Pixel)
  1. pixel

Simple English

[[File:|frame|right|Pixels in the picture of a computer.]] A pixel (short for picture element) is a single point in a picture. On the monitor of a computer, a pixel is usually a square. Every pixel has a color and all the pixels together are the picture. The color of a pixel can be stored by using a combination of red, green and blue (RGB) but other combinations are also possible, such as cyan, magenta, yellow and black (CMYK).

The word "pixel"

The word "pixel" was first used in a paper by Frederic C. Billingsley in 1965. He did not create the word himself. He got it from Keith E. McFarland but Keith does not know where he got it from. Keith said that the word was in use in those days.

The word "pixel" uses "pix" as a shorter word (an abbreviation) for "picture". The word pix was first used in 1932 in Variety, a magazine. It was an abbreviation for "pictures" or movies. By 1938 the word "pix" was also used for pictures that did not move (still pictures).

The word "picture element" is even older. For example, the German word Bildpunkt (which means "picture point") was used in a 1888 patent of Paul Gottlieb Nipkow.

Other pages


Citable sentences

Up to date as of December 29, 2010

Here are sentences from other pages on Pixel, which are similar to those in the above article.








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