Week 10: Text Objects 2

Summary

We will learn about the digitization of text-based media, or “text objects,” like books, manuscripts, comics, notebooks, etc. We will learn about character encodings, optical character recognition (OCR), and typical workflows for text digitization.

Weekly Learning Objectives

• distinguish between a “textual image” and a “text file” and explain the functional differences between the two
• define character encoding, ASCII, and Unicode
• use tesseract to perform OCR on image files
• diagram a typical text digitization workflow

Before class: Readings, Resources, and Tasks

Readings

• Read Witten Ch. 3, pp. 73-86 and Ch. 4, pp. 127-152.
• Willett, P. (2004). “Electronic Texts: Audiences and Purposes.” from A Companion to Digital Humanities at http://digitalhumanities.org:3030/companion/view?docId=blackwell/9781405103213/9781405103213.xml&chunk.id=ss1-3-6&toc.depth=1&toc.id=ss1-3-6.
• Christenson, H. (2010). “HathiTrust: A Research Library at Web Scale.” Library Resources and Technical Services 55(2). pp. 93-102. https://www.hathitrust.org/documents/christenson-lrts-201104.pdf

Tasks

• Install tesseract
  • On mac, use the homebrew command brew install tesseract.
    • Homebrew is package manager that simplifies the process of installing Unix software on your Mac. Installation instructions are available at https://brew.sh.
  • On windows, use the installer availabe at https://github.com/UB-Mannheim/tesseract/wiki
• Install Adobe Acrobat from https://iuware.iu.edu/.

In Class

• slides
• Metadata Crosswalking Lab
• OCR exercise
• Linux/Mac Commandline Cheat Sheet (you’ll mostly need the directory commands)
• Windows Commandline Cheat Sheet by Stephen Edwards at Columbia University