I'll bet libraries around the world would love to see an "augmented reality" application to record/display all the highlighting a person would want to do without actually marking any pages.

And you wouldn't be tied to a particular single copy of whatever you're reading & hightlighting, or highlit  when you read it somewhere else n years ago.

Paul, what an excellent suggestion. Also at the perfect time since, because I wanted to enter the Hackaday prize, I was still looking for a hardware aspect to this software project.

Next to the obvious digitizing use case I mainly came up with comparing how students learn differently from each other by analyzing what and where they highlight.

All in all completing this project will be a major challenge (even without the AR which I have no experience with) but it is very nice to have a point on the horizon. Thanks for your contribution.

You're welcome! and welcome to use & extend the idea as you wish, in case that wasn't obvious.