Digital image

نوشته شده در موضوع خرید اینترنتی در 22 آوریل 2017

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A digital image is a numeric illustration of (normally binary) a two-dimensional image. Depending on either a design fortitude is fixed, it might be of matrix or raster type. By itself, a tenure “digital image” customarily refers to raster images or bitmapped images.


Raster images have a calculable set of digital values, called picture elements or pixels. The digital design contains a bound series of rows and columns of pixels. Pixels are a smallest particular component in an image, holding superannuated values that paint a liughtness of a given tone during any specific point.

Typically, a pixels are stored in mechanism memory as a raster design or raster map, a two-dimensional array of tiny integers. These values are mostly transmitted or stored in a dense form.

Raster images can be total by a accumulation of submit inclination and techniques, such as digital cameras, scanners, coordinate-measuring machines, seismographic profiling, airborne radar, and more. They can also be synthesized from capricious non-image data, such as mathematical functions or three-dimensional geometric models; a latter being a vital sub-area of mechanism graphics. The margin of digital design estimate is a investigate of algorithms for their transformation.

Raster record formats[edit]

Most users come into hit with raster images by digital cameras, that use any of several design record formats.

Some digital cameras give entrance to roughly all a information prisoner by a camera, regulating a tender design format. The Universal Photographic Imaging Guidelines (UPDIG) suggests these formats be used when probable given tender files furnish a best peculiarity images. These record formats concede a photographer and a estimate representative a biggest turn of control and correctness for output. Their use is indifferent by a superiority of exclusive information (trade secrets) for some camera makers, though there have been initiatives such as OpenRAW to change manufacturers to recover these annals publicly. An choice might be Digital Negative (DNG), a exclusive Adobe product described as “the public, archival format for digital camera tender data”.[1] Although this format is not nonetheless zodiacally accepted, support for a product is growing, and increasingly veteran archivists and conservationists, operative for important organizations, variously advise or suggest DNG for archival purposes.[2][3][4][5][6][7][8][9][10]


Vector images resulted from mathematical geometry (vector). In mathematical terms, a matrix consists of indicate that has both instruction and length.

Often, both raster and matrix elements will be total in one image; for example, in a box of a billboard with content (vector) and photographs (raster).

Image viewing[edit]

Image spectator module displays images. Web browsers can arrangement customary internet design formats including GIF, JPEG, and PNG. Some can uncover SVG format that is a customary W3C format. In a past, when Internet was still slow, it was common to yield “preview” design that would bucket and seem on a web site before being transposed by a categorical design (to give during rough impression). Now Internet is quick adequate and this preview design is occasionally used.

Some systematic images can be really vast (for instance, a 46 gigapixel distance design of a Milky Way, about 194 Gb in size). [11] Such images are formidable to download and are customarily browsed online by some-more formidable web interfaces.

Some viewers offer a slideshow application to arrangement a method of images.


Early Digital fax machines such as a Bartlane wire design delivery complement preceded digital cameras and computers by decades. The initial design to be scanned, stored, and recreated in digital pixels was displayed on a Standards Eastern Automatic Computer (SEAC) during NIST.[12] The enrichment of digital imagery continued in a early 1960s, alongside growth of a space module and in medical research. Projects during a Jet Propulsion Laboratory, MIT, Bell Labs and a University of Maryland, among others, used digital images to allege satellite imagery, wirephoto standards conversion, medical imaging, videophone technology, impression recognition, and print enhancement.[13]

Rapid advances in digital imaging began with a introduction of microprocessors in a early 1970s, alongside swell in associated storage and arrangement technologies. The invention of computerized axial tomography (CAT scanning), regulating x-rays to furnish a digital design of a “slice” by a three-dimensional object, was of good significance to medical diagnostics. As good as fad of digital images, digitization of analog images authorised a encouragement and replacement of archaeological artifacts and began to be used in fields as different as chief medicine, astronomy, law enforcement, counterclaim and industry.[14]

Advances in microprocessor record paved a approach for a growth and selling of charge-coupled inclination (CCDs) for use in a far-reaching operation of design constraint inclination and gradually replaced a use of analog film and fasten in photography and videography towards a finish of a 20th century. The computing energy required to routine digital design constraint also authorised computer-generated digital images to grasp a turn of excellence tighten to photorealism.[15]

See also[edit]

  • Computer graphics portal
  • Computer printer
  • Digital design editing
  • Digital geometry
  • Digital photography
  • Geocoded photo
  • Optical impression recognition
  • Signal processing
  • Digital design correlation


  1. ^ Digital Negative (DNG) Specification. San Jose: Adobe, 2005. Vers. p. 9. Accessed on Oct 10, 2007.
  2. ^ universal detailed digital imaging discipline (UPDIG): File formats – a tender record issue
  3. ^ Archaeology Data Service / Digital Antiquity: Guides to Good Practice – Section 3 Archiving Raster Images – File Formats
  4. ^ University of Connecticut: “Raw as Archival Still Image Format: A Consideration” by Michael J. Bennett and F. Barry Wheeler
  5. ^ Inter-University Consortium for Political and Social Research: Obsolescence – File Formats and Software
  6. ^ JISC Digital Media – Still Images: Choosing a File Format for Digital Still Images – File formats for master archive
  7. ^ International Digital Enterprise Alliance, Digital Image Submission Criteria (DISC) Guidelines Specifications 2007 (PDF)
  8. ^ The J. Paul Getty Museum – Department of Photographs: Rapid Capture Backlog Project – Presentation
  9. ^ American Institute for Conservation – Electronic Media Group: Digital Image File Formats
  10. ^ Archives Association of British Columbia: Born Digital Photographs: Acquisition and Preservation Strategies (Rosaleen Hill)
  11. ^
  12. ^ Fiftieth Anniversary of First Digital Image.
  13. ^ Azriel Rosenfeld, Picture Processing by Computer, New York: Academic Press, 1969
  14. ^ Gonzalez, Rafael, C; Woods, Richard E (2008). Digital Image Processing, 3rd Edition. Pearson Prentice Hall. p. 577. ISBN 978-0-13-168728-8. 
  15. ^ Jähne, Bernd (1993). Spatio-temporal design processing, Theory and Scientific Applications. Springer Verlag. p. 208. ISBN 3-540-57418-2. 











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