Fast Document Rectification and Enhancement

I wonder if the lines can also be automatically removed like the ones from the last gif.

Currently I'm using http://whitelines.se paper but it's expensive.

I checked to make sure my dropbox app is updated. Is this feature only available on iphone, or is it part of their paid service?

Looks like they are using a 2D model for the paper being imaged. This won't work for curved/folded pages like something from a book

This is one of my favorite features of Evernote. Looking forward to giving it a try.

What is the difference between this and CamScanner?

CamScanner seems to be a smartphone application for scanning documents; this seems to be an article that explains how Dropbox has implemented their document scanning functionality.