Optical character recognition, or OCR,
is the conversion of text captured in images into text usable by a computer.
In other words, an OCR tool can read the text in images.
OCR is a common method of processing large volumes of printed text,
especially when that text isn't available in a digital format.
In practical applications, OCR has been used to scan the pages of books,
to recognize license plates, and even to convert handwriting into digitized text.
Let me share an example from my own work.
During my doctoral degree I was working on an open source system called
Opencast Matterhorn.
This system allows for the automated recording of lectures within universities,
similar in some ways to the video you're watching now.
The system generally ran automatically when an instructor was teaching a course.
And the video was uploaded to the web immediately following
the lecture without any input from technicians.
This was great, but it was hard to find videos about your given topic that
might have been covered during the lecture.
To deal with this we built a search index from the contents of videos themselves.
We essentially broke a video up into a sequence of images.
Ran OCR on each image to determine what text might have been shown to the students
from the slides in the classroom.
Then created a search index using this technique.
In the project for this course, you're going to be doing something similar.
But we're going to be doing it with images of newspapers instead.
In this module of the course,
we're going to be using an OCR engine called Tesseract.
Tesseract was originally developed between 1984 and
1994 as a PhD research project at HP labs.
The engine vastly outperform commercial products at the time, but
then development was stopped until HP released Tesseract as open source in 2005.
In 2006, Google began maintaining the tool and has since released
updated versions of Tesseract with support for over 100 languages.
I think Tesseract is a great tool, and a wonderful example of how companies can
engage in open source software development.
So before we spend a lot of time talking about Tesseract,
let's talk more about open source software.