DjVu – Guy Rutenberg

A new semester is about to begin, so I again set out to organize lecture notes and scan them. This time I intend to invest more time in investigating and perfecting this process. Hopefully, I’ll present my conclusions in a few posts, each focusing on a different aspect.

In the first post, I’ll discuss the various ways to compress scanned lecture notes. Because lecture notes (at least mine) aren’t especially colorful, as I only use one pen at a time, I want the result to be black and white (line art). This allows for readable lecture notes while preserving a small size per page (as you can see in Some Tips on Scanning Lecture Notes).
Continue reading Scanning Lecture Notes – Compression

I’ve decided to scan some notebooks. After researching a bit, I’ve decided to use DjVu instead of PDF, which I normally use. I’ve chosen to use DjVu because it offered great quality with a very good compression rate (~26KB per page) in lineart (black and white).

While XSane can natively save a multipage project into PDF, it can’t do so for DjVu. So the solution is to use the PNMs generated by XSane and convert them using the command line tools offered by DjVuLibre to bundle them together into a DjVu file. As you can guess, doing this manually is pretty hard work. To make this task easier, I’ve written a small bash script to automate the process.
Continue reading Convert PNMs to DjVu