Your SlideShare is downloading. ×
  • Like
Digitisation Doctor Optical Character Recognition
Upcoming SlideShare
Loading in...5

Thanks for flagging this SlideShare!

Oops! An error has occurred.


Now you can save presentations on your phone or tablet

Available for both IPhone and Android

Text the download link to your phone

Standard text messaging rates apply

Digitisation Doctor Optical Character Recognition


Optical Character Recognition guidance and advice

Optical Character Recognition guidance and advice

Published in Technology , Business
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Be the first to comment
No Downloads


Total Views
On SlideShare
From Embeds
Number of Embeds



Embeds 0

No embeds

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

    No notes for slide


  • 1. Simon TannerBlog: @SimonTanner
  • 2. King’s Digital Consultancy Services
  • 3. Deciding whether Optical Character Recognition is feasible(PDF document) created for the Oxford University Mass Text Digitization Quality and Usefulness:Lessons Learned from Assessing the OCR Accuracy of theBritish Librarys 19th Century Online Newspaper
  • 4. UniformityLanguageText alignmentComplexity of alignmentLines, graphics and picturesHandwriting
  • 5. Evaluating OCR accuracy is about more than justcharacter to character accuracy rates Character accuracy rates are misleading (more later…)It is also about assessing the functionality enabledthrough the OCR’s output Search accuracy Volume of hits returned Ability to structure searches and results Accuracy of result ranking Amount of correction required to achieve the required performance
  • 6. Consider this scenario: 1,000 words with 5,000 characters (an average of 5 per word) excluding spaces 90% character accuracy means: 4,500 characters correct Possibly a maximum 900 words correct (90%) Possibly a minimum 500 words correct (50%) Reality is somewhere in between Depending on the number of “significant words” the search results could still be almost 100% or near zero
  • 7. 1009080706050 1801 1810 1820 1830 1840 1850 1860 1870 1880 1890 1900 characters words words with capital letter start significant words Poly. (characters) Poly. (words) Poly. (significant words) Poly. (words with capital letter start
  • 8. OCR Results % characters % words correct No. of corrections OCR Engine correct FineReader 91.1 70.9 110 PrimeOCR 93.95 79.1 79Total number of characters = 2109Total number of words = 379 I am petfood, God toil! uttedy-toverthroW, at feaft; $gy abafe Mens affections tp; and seal for all Party-making Notions amdngft CfiriftiansybefGieirie will raife his,Church to that prof- perous, flourilhing State prophefied of, and prOmifed in the Scrip* tures. There mult be more Love, and Charity, and Unanimity amongft Chriftians,.
  • 9. OCR Results % characters % words correct No. of correctionsOCR Engine correctFineReader 73.7 57.5 31PrimeOCR 75.9 62.37 28Total number of characters = 411Total number of words = 73 A THEATRE erein be reprc-fented as wel the miferies & calamities tijat foiioto tht too* e^jr alfo the greate toyts and plefures tobtcf) tbe fatrfc faltooenio^ An Argument both profitable and dele&able, to all that finccrcly loue the word of Codt. *Deuifedby S. hhnv&n~ derlS^oodt. s 3^ Scene and allowed according to the order appointed. , ^ Imprinted at London by Henry Bynncman* Anno Domini. CVM PHIT
  • 10. Simon TannerBlog: @SimonTanner