Editing Digital image (section)

==History==
{{See|Digital imaging#History|Digital image processing#History}}
[[File:NBSFirstScanImageRestored.jpg|right|thumb|The first scan done by the [[SEAC (computer)|SEAC]] in 1957]]
[[File:SEACComputer 031.jpg|right|thumb|The SEAC scanner]]

Early [[Fax machine#Digital|digital fax]] machines such as the [[Bartlane cable picture transmission system]] preceded digital cameras and computers by decades.
The first picture to be scanned, stored, and recreated in digital pixels was displayed on the Standards Eastern Automatic Computer ([[SEAC (computer)|SEAC]]) at [[NIST]].<ref>[https://www.sciencecodex.com/fiftieth_anniversary_of_first_digital_image''Fiftieth Anniversary of First Digital Image''] {{Webarchive|url=https://web.archive.org/web/20101014030023/https://www.sciencecodex.com/fiftieth_anniversary_of_first_digital_image |date=2010-10-14 }}.</ref> The advancement of digital imagery continued in the early 1960s, alongside development of the [[space program]] and in [[medicine|medical]] research. Projects at the [[Jet Propulsion Laboratory]], [[MIT]], [[Bell Labs]] and the [[University of Maryland, College Park|University of Maryland]], among others, used digital images to advance [[satellite imagery]], wirephoto standards conversion, [[medical physics|medical imaging]], [[videophone]] technology, [[character recognition]], and photo enhancement.<ref>Azriel Rosenfeld, ''Picture Processing by Computer'', New York: Academic Press, 1969</ref>

Rapid advances in [[digital imaging]] began with the introduction of [[MOS integrated circuit]]s in the 1960s and [[microprocessor]]s in the early 1970s, alongside progress in related [[computer memory]] storage, [[display technologies]], and [[data compression]] algorithms.

The invention of computerized axial tomography ([[CAT scanning]]), using [[x-ray]]s to produce a digital image of a "slice" through a three-dimensional object, was of great importance to medical diagnostics. As well as origination of digital images, [[digitization]] of analog images allowed the enhancement and restoration of [[archaeology|archaeological]] artifacts and began to be used in fields as diverse as [[nuclear medicine]], [[astronomy]], [[Law enforcement agency|law enforcement]], [[defence (military)|defence]] and [[Private industry|industry]].<ref>
{{cite book
  | last = Gonzalez
  | first = Rafael, C
  |author2=Woods, Richard E
  | title = Digital Image Processing, 3rd Edition
  | publisher = Pearson Prentice Hall
  | year = 2008
  | page = 577
  | url = https://books.google.com/books?id=8uGOnjRGEzoC&q=%22digital+image+processing%22+gonzalez
  | isbn = 978-0-13-168728-8}}
</ref>

Advances in microprocessor technology paved the way for the development and marketing of [[charge-coupled device]]s (CCDs) for use in a wide range of [[image capture]] devices and gradually displaced the use of analog [[photographic film|film]] and [[videotape|tape]] in photography and videography towards the end of the 20th century. The computing power necessary to process digital image capture also allowed [[computer graphics#History|computer-generated]] digital images to achieve a level of refinement close to [[Photorealistic rendering|photorealism]].<ref>
{{cite book
  | last = Jähne
  | first = Bernd
  | title = Spatio-temporal image processing, Theory and Scientific Applications
  | publisher = Springer Verlag
  | year = 1993
  | page = 208
  | url = https://books.google.com/books?id=gO6V5gh4IXsC&q=Spatio-temporal+image+processing
  | isbn = 3-540-57418-2}}
</ref>

===Digital image sensors===
{{Main|Image sensor}}

The first semiconductor image sensor was the CCD, developed by [[Willard S. Boyle]] and [[George E. Smith]] at Bell Labs in 1969.<ref>{{Cite book | title = Scientific charge-coupled devices | author = James R. Janesick | publisher = SPIE Press | year = 2001 | isbn = 978-0-8194-3698-6 | pages = 3–4 | url = https://books.google.com/books?id=3GyE4SWytn4C&pg=PA3 | access-date = 2020-06-06 | archive-date = 2020-11-15 | archive-url = https://web.archive.org/web/20201115062950/https://books.google.com/books?id=3GyE4SWytn4C&pg=PA3 | url-status = live }}</ref> While researching MOS technology, they realized that an electric charge was the analogy of the magnetic bubble and that it could be stored on a tiny [[MOS capacitor]]. As it was fairly straightforward to [[semiconductor device fabrication|fabricate]] a series of MOS capacitors in a row, they connected a suitable voltage to them so that the charge could be stepped along from one to the next.<ref name="Williams">{{cite book|last1=Williams|first1=J. B.|url=https://books.google.com/books?id=v4QlDwAAQBAJ&pg=PA245|title=The Electronics Revolution: Inventing the Future|date=2017|publisher=Springer|isbn=978-3-319-49088-5|pages=245–8|access-date=2019-10-10|archive-date=2020-11-15|archive-url=https://web.archive.org/web/20201115080239/https://books.google.com/books?id=v4QlDwAAQBAJ&pg=PA245|url-status=live}}</ref> The CCD is a semiconductor circuit that was later used in the first [[digital video camera]]s for [[television broadcasting]].<ref>{{cite journal|last1=Boyle|first1=William S|last2=Smith|first2=George E.|date=1970|title=Charge Coupled Semiconductor Devices|journal=Bell Syst. Tech. J.|volume=49|issue=4|pages=587–593|doi=10.1002/j.1538-7305.1970.tb01790.x|bibcode=1970BSTJ...49..587B }}</ref>

Early CCD sensors suffered from [[shutter lag]]. This was largely resolved with the invention of the [[pinned photodiode]] (PPD).<ref name="Fossum2014"/> It was invented by [[Nobukazu Teranishi]], Hiromitsu Shiraki and Yasuo Ishihara at [[NEC]] in 1980.<ref name="Fossum2014"/><ref>{{US patent|4484210|U.S. Patent 4,484,210: Solid-state imaging device having a reduced image lag}}</ref> It was a [[photodetector]] structure with low lag, low [[noise (electronics)|noise]], high [[quantum efficiency]] and low [[dark current (physics)|dark current]].<ref name="Fossum2014"/> In 1987, the PPD began to be incorporated into most CCD devices, becoming a fixture in [[consumer electronic]] [[video cameras]] and then [[digital still camera]]s. Since then, the PPD has been used in nearly all CCD sensors and then CMOS sensors.<ref name="Fossum2014"/>

The [[NMOS logic|NMOS]] [[active-pixel sensor]] (APS) was invented by [[Olympus Corporation|Olympus]] in Japan during the mid-1980s. This was enabled by advances in MOS [[semiconductor device fabrication]], with [[MOSFET scaling]] reaching smaller [[List of semiconductor scale examples|micron and then sub-micron]] levels.<ref name=fossum93>{{cite book |last1=Fossum |first1=Eric R. |chapter=Active pixel sensors: Are CCDS dinosaurs? |author1-link=Eric Fossum |title=Charge-Coupled Devices and Solid State Optical Sensors III |journal=SPIE Proceedings Vol. 1900: Charge-Coupled Devices and Solid State Optical Sensors III |date=12 July 1993 |volume=1900 |doi=10.1117/12.148585 |publisher=International Society for Optics and Photonics |pages=2–14 |bibcode=1993SPIE.1900....2F |editor1-last=Blouke |editor1-first=Morley M.|citeseerx=10.1.1.408.6558 |s2cid=10556755 }}</ref><ref>{{cite web |last1=Fossum |first1=Eric R. |author1-link=Eric Fossum |date=2007 |title=Active Pixel Sensors |website=Eric Fossum |url=https://ericfossum.com/Publications/Papers/Active%20Pixel%20Sensors%20LASER%20FOCUS.pdf |s2cid=18831792}}</ref> The NMOS APS was fabricated by Tsutomu Nakamura's team at Olympus in 1985.<ref>{{cite journal |last1=Matsumoto |first1=Kazuya |last2=Nakamura |first2=Tsutomu |last3=Yusa |first3=Atsushi |last4=Nagai |first4=Shohei |display-authors=1|date=1985 |title=A new MOS phototransistor operating in a non-destructive readout mode |journal=Japanese Journal of Applied Physics |volume=24 |issue=5A |page=L323|doi=10.1143/JJAP.24.L323 |bibcode=1985JaJAP..24L.323M |s2cid=108450116 }}</ref> The [[CMOS]] active-pixel sensor (CMOS sensor) was later developed by [[Eric Fossum]]'s team at the [[NASA]] [[Jet Propulsion Laboratory]] in 1993.<ref name="Fossum2014">{{cite journal |last1=Fossum |first1=Eric R. |author1-link=Eric Fossum |last2=Hondongwa |first2=D. B. |title=A Review of the Pinned Photodiode for CCD and CMOS Image Sensors |journal=IEEE Journal of the Electron Devices Society |date=2014 |volume=2 |issue=3 |pages=33–43 |doi=10.1109/JEDS.2014.2306412 |doi-access=free }}</ref> By 2007, sales of CMOS sensors had surpassed CCD sensors.<ref>{{cite news |title=CMOS Image Sensor Sales Stay on Record-Breaking Pace |url=https://www.icinsights.com/news/bulletins/CMOS-Image-Sensor-Sales-Stay-On-RecordBreaking-Pace/ |access-date=6 October 2019 |work=IC Insights |date=May 8, 2018 |archive-date=21 June 2019 |archive-url=https://web.archive.org/web/20190621180401/https://www.icinsights.com/news/bulletins/CMOS-Image-Sensor-Sales-Stay-On-RecordBreaking-Pace/ |url-status=live }}</ref>

===Digital image compression===
{{Main|Image compression}}

An important development in digital [[image compression]] technology was the [[discrete cosine transform]] (DCT), a [[lossy compression]] technique first proposed by [[N. Ahmed|Nasir Ahmed]] in 1972.<ref name="Ahmed">{{cite journal |last=Ahmed |first=Nasir |author-link=N. Ahmed |title=How I Came Up With the Discrete Cosine Transform |journal=[[Digital Signal Processing (journal)|Digital Signal Processing]] |date=January 1991 |volume=1 |issue=1 |pages=4–5 |doi=10.1016/1051-2004(91)90086-Z |bibcode=1991DSP.....1....4A |url=https://www.scribd.com/doc/52879771/DCT-History-How-I-Came-Up-with-the-Discrete-Cosine-Transform |access-date=2019-09-14 |archive-date=2016-06-10 |archive-url=https://web.archive.org/web/20160610013109/https://www.scribd.com/doc/52879771/DCT-History-How-I-Came-Up-with-the-Discrete-Cosine-Transform |url-status=live |url-access=subscription }}</ref> DCT compression is used in [[JPEG]], which was introduced by the [[Joint Photographic Experts Group]] in 1992.<ref name="t81">{{cite web |title=T.81 – Digital Compression and Coding of Continuous-Tone Still Images – Requirements and Guidelines |url=https://www.w3.org/Graphics/JPEG/itu-t81.pdf |publisher=[[CCITT]] |date=September 1992 |access-date=12 July 2019 |archive-date=30 December 2019 |archive-url=https://web.archive.org/web/20191230093239/https://www.w3.org/Graphics/JPEG/itu-t81.pdf |url-status=live }}</ref> JPEG compresses images down to much smaller file sizes, and has become the most widely used image file format on the [[Internet]].<ref>{{cite web |title=The JPEG image format explained |url=https://home.bt.com/tech-gadgets/photography/what-is-a-jpeg-11364206889349 |website=[[BT.com]] |publisher=[[BT Group]] |access-date=5 August 2019 |date=31 May 2018 |archive-date=5 August 2019 |archive-url=https://web.archive.org/web/20190805194553/https://home.bt.com/tech-gadgets/photography/what-is-a-jpeg-11364206889349 }}</ref>