1. KB pilot OCR correction
Judith Rog, 26 juni 2012, Impact Final Event

2. EDBO Pilot OCR Correction
Early Dutch Books Online (EDBO)
• Special Collections of the University libraries of Leiden and
Amsterdam and the KB
• Concentrating on historical, political, theological, and literary
works from the period of 1781 to1800
• +/- 11.000 books +/- 2.ooo.ooo pages
• For each page:
• Image
• ALTO
• Txt file
• For each book :
• MPEG21
• PDF
• Website: www.earlydutchbooksonline.nl
Koninklijke Bibliotheek – National Library of the Netherlands

3. EDBO Pilot OCR Correction
Early Dutch Books Online (EDBO)
• Website:
Koninklijke Bibliotheek – National Library of the Netherlands

4. EDBO Pilot OCR Correction
Early Dutch Books Online (EDBO)
• Website:
Koninklijke Bibliotheek – National Library of the Netherlands

5. EDBO Pilot OCR Correction
OCR-quality
• Voorbeelden van boeken met voorkomende fouten link
naar Impact leggen
Koninklijke Bibliotheek – National Library of the Netherlands

6. EDBO Pilot OCR Correction
Early Dutch Books Online (EDBO)
• Website and data were delivered, 1st stage project ended.
• What to do next?
Koninklijke Bibliotheek – National Library of the Netherlands

7. EDBO Pilot OCR Correction
EDBO-OCR-Quality
Koninklijke Bibliotheek – National Library of the Netherlands

8. EDBO Pilot OCR Correction
EDBO-OCR-Quality
Koninklijke Bibliotheek – National Library of the Netherlands

9. EDBO Pilot OCR Correction
Koninklijke Bibliotheek – National Library of the Netherlands

10. EDBO Pilot OCR Correction
Improve Quality OCR  more specific word
accuracy to improve searching
Visit to the Impact colleagues down the
hall….
•What is available on short term?
•Bad timing
•Evaluation/pilot
Koninklijke Bibliotheek – National Library of the Netherlands

11. EDBO Pilot OCR Correction
Set-up: books
2. Title: Verzameling van placaaten, resolutien en andere authentyke stukken enz. betrekking
hebbende tot de gewigtige gebeurtenissen, in de maand september MDCCLXXXVII, bevooren
en vervolgens, in het gemeenebest der Vereenigde Nederlanden voorgevallen. : Part 29
• Year: 1791
• Copy: Leiden, Universiteitsbibliotheek: 1006 A 29
• No. of pages: 338
3. Title: Verhandelingen van het Genootschap ter bevordering der heelkunde, te Amsterdam. :
Part 1
• Year: 1791
• Copy: Leiden, Universiteitsbibliotheek: 1448 G 2
• No. of pages: 331
• Ground-truth
• Large numbers of pages
Koninklijke Bibliotheek – National Library of the Netherlands

12. EDBO Pilot OCR Correction
Set-up
Alto Edit LMU PlaIR
Person 1 Set 1-1 Set 1-2 Set 2-1
Person 2 Set 1-2 Set 1-3 Set 2-2
Person 3 Set 1-3 Set 1-1 -
Person 4 Set 2-1 Set 2-2 Set 1-1
Person 5 Set 2-2 Set 2-3 Set 1-2
Person 6 Set 2-3 Set 2-1 Set 1-3
• Before the first tool: general introduction, guidelines,
introduction on 18th century books
• Training session: 2.5 hrs per tool in the afternoon
• Next morning: 3 hrs correction, 15 min break
• 6 humanities students
Koninklijke Bibliotheek – National Library of the Netherlands

13. Pilot set-up: tools  AltoEdit KBEDBO Pilot OCR Correction
KB Alto Edit main screen
Koninklijke Bibliotheek – National Library of the Netherlands

14. Pilot set-up: tools  AltoEdit KBEDBO Pilot OCR Correction
Segmentation correction in Alto Edit
Koninklijke Bibliotheek – National Library of the Netherlands

15. Pilot set-up: tools  LMU EDBO Pilot OCR Correction
Overview LMU Post Correction Tool
Koninklijke Bibliotheek – National Library of the Netherlands

16. Pilot set-up: tools  LMU EDBO Pilot OCR Correction
Batch correction by error pattern (n>u>
Batch correct by word
Koninklijke Bibliotheek – National Library of the Netherlands

17. Pilot set-up: tools  PlaIR EDBO Pilot OCR Correction
Overview PlaIR platform
Koninklijke Bibliotheek – National Library of the Netherlands

18. Pilot set-up: tools  PlaIR EDBO Pilot OCR Correction
PlaIR Correction mode
Koninklijke Bibliotheek – National Library of the Netherlands

19. EDBO Pilot OCR Correction
Set-up: tools
Tools for post-correction
• AltoEdit KB
• LMU Profiler and Post Correction Tool
• PlaIR (LITIS Laboratory - Rouen)
• (IBM Concert)
Re-OCR
• Adaptive OCR
• ABBYY FRE 10 with internal dictionaries
• ABBYY FRE 10 with IMPACT Historical Dictionary as developed
in Impact
Koninklijke Bibliotheek – National Library of the Netherlands

20. Comments EDBO Pilot OCR Correction
•Familiarity to the material and the
guidelines
•Boredom
•Functionalities differ
•LMU for large sets
•PlaIR for newspapers
•Not the same base set of OCR for LMU
Koninklijke Bibliotheek – National Library of the Netherlands

21. Conclusion
• The goal of any OCR improvement project is very important in choosing
the correct tool:
• Crowdsourcing and little resources?  Basic tools
• ALTO Edit
• PlaIR
• More functionalities and resources?  Advanced tools
• LMU’s Profiler and Post correction tool
• CONCERT
• Automated process with least amount of effort?  re-OCRing
• ABBYY FRE10
• Internal dictionary
• Historical dictionary
• IBM’s Adaptive OCR
• Ideally, all material is re-OCRed before any post correction, resulting in
the highest possible word accuracy.
Koninklijke Bibliotheek – National Library of the Netherlands

22. EDBO Pilot OCR Correction
Koninklijke Bibliotheek – National Library of the Netherlands