Joan L. Mitchell

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Joan L. Mitchell
Joan Laverne Mitchell.jpg
A JPEG picture of Joan L. Michell
Born(1947-05-24)May 24, 1947
DiedDecember 2, 2015(2015-12-02) (aged 68)
Alma materStanford University, University of Illinois at Urbana–Champaign
Known forCo-inventer of JPEG digital image format.
RelativesEulalia Richardson Mitchell (grandmother, Physicist)

Joan Laverne Mitchell (May 24, 1947 – December 2, 2015)[1][2] was an American computer scientist, data compression pioneer, and inventor who, as a researcher at IBM, coinvented the JPEG digital image format.[3]

Early life[edit]

Mitchell was born on May 24, 1947, in Modesto, California. Mitchell's father was William Mitchell and her mother was Doris Mitchell. [2]


Mitchell was a National Merit Scholar at Stanford University, where her work included an independent study project on Brillouin scattering in bromine.[1] In 1969, Mitchell graduated with a Bachelor of Science degree in physics from Stanford University[1][4] with distinction[5] and Phi Beta Kappa.[1] She followed in the footsteps of her grandmother, Eulalia Richardson Mitchell, who also earned Stanford physics degrees in 1910 and 1912.[1][6]

Mitchell went on to graduate study in condensed matter physics at the University of Illinois at Urbana–Champaign, and earned a master's degree in 1971 and a Ph.D. in 1974 there.[1][3][4] As part of her Ph.D. work, she also learned computer programming, so that she could use a computer to solve the differential equations arising in her research.[1] Her dissertation, Effect of heterovalent impurities co-diffusing with monovalent tracers in ionic crystals, was supervised by David Lazarus.[7]

Career and later life[edit]

Mitchell began working at the IBM Thomas J. Watson Research Center in 1974, in the Exploratory Printing Technologies Group.[3][4] There, her inventions included a method for ultrasonic printing, a method for thermal-transfer printing later used in some models of the IBM Selectric typewriter, data compression for fax machines, a teleconferencing system,[3] and the Q-coder method for arithmetic coding used in JBIG image compression.[1] From 1987 to 1994, Mitchell helped develop the JPEG standard, and she became a coauthor with Bill Pennebaker of the first book on the standard.[1][3][4] Gregory K. Wallace, another member of the group, remembers Mitchell and Pennebaker as "two of the most insightful, energetic, and prolific members" of the Joint Photographic Experts Group.[8]

During the mid-1990s Mitchell moved from the Watson Research Center to a different IBM group in Vermont and then (after a short leave as a visiting professor at the University of Illinois) to IBM's Printing Systems Division in Colorado.[3][4] In 2007 IBM sold their Printing Systems Division to Ricoh,[9] and Mitchell went with them to the resulting joint venture, InfoPrint Solutions. She retired in 2009,[10] and died on December 2, 2015.[2]


Mitchell became an IEEE Fellow in 1999 "for contributions to the development of international image compression standards",[11] an IBM Fellow in 2001,[3][4] and, in 2004, a member of the National Academy of Engineering "for leadership in setting standards for the formation of photographic fax and image compression".[1] She was the 2011 winner of the IEEE Masaru Ibuka Consumer Electronics Award,[1][10] and is listed in the Hall of Fame of distinguished alumni of the University of Illinois at Urbana–Champaign.[3]


Mitchell is the author of:

  • JPEG: Still Image Data Compression Standard (with William B. Pennebaker, Van Nostrand Reinhold, 1992)[12]
  • MPEG Video Compression Standard (with William B. Pennebaker, Chad Fogg, and Didier J. LeGall, Chapman and Hall, 1997)[13]
  • Dr. Joan's Mentoring Book: Straight Talk about Taking Charge of Your Career (with Nancy Walker-Mitchell, 2007)[1][10]


  1. ^ a b c d e f g h i j k l Hahn, Laura D.; Wolters, Angela S. (2018), "Joan Mitchell (1947–2015), with Celia M. Elliott", Women and Ideas in Engineering: Twelve Stories from Illinois, University of Illinois Press, ISBN 9780252050671
  2. ^ a b c "Joan Mitchell (1947–2015)", Obituaries, Modesto Bee, December 9, 2015 – via
  3. ^ a b c d e f g h "Joan L. Mitchell: Leading developer of image compression methods; coinventor of jpeg", Distinguished Alumni and Friends: Hall of Fame, University of Illinois at Urbana–Champaign College of Engineering, retrieved 2018-10-21
  4. ^ a b c d e f "Joan Mitchell", IBM Women in Technology: IBM Women Fellows, IBM, retrieved 2018-10-21
  5. ^ "311 to graduate with honors", The Stanford Daily, 155 (64), May 21, 1969
  6. ^ Eulalia Richardson Mitchell scrapbook, 1906–1911, Stanford University Library, Special Collections, retrieved 2018-10-22
  7. ^ Mitchell, Joan Laverne (1974), Effect of heterovalent impurities co-diffusing with monovalent tracers in ionic crystals, University of Illinois – via Illinois Digital Environment for Access to Learning and Scholarship
  8. ^ Wallace, Gregory K. (1992), Foreword to JPEG: Still Image Data Compression Standard, Kluwer, pp. xiii–xiv
  9. ^ IBM sells printing division to Ricoh, UPI, January 26, 2007, retrieved 2018-10-21
  10. ^ a b c InfoPrint Solutions Company Master Inventor and Fellow Wins Prestigious IEEE Award for Globally Recognized Developments, Ricoh, September 8, 2010, retrieved 2018-10-21
  11. ^ IEEE Fellows Elected as of 1 January 1999, IEEE Communications Society, retrieved 2018-10-21
  12. ^ Review of JPEG: Still Image Data Compression Standard:
  13. ^ Reviews of MPEG Video Compression Standard:

External links[edit]