Tried many scanners. Finally resorted to this one.

So Ive gone through a lot scanner apps...and have been using Camscanner Pro for a while. I have to scan a 1000-page book, and finally resorted to sticking with this one after trying so many. After you take a picture, the detection lines are one of the most - if not, the most - easily accommodating to adjustment when you adjust the borders. Also, the filters final product is the most superior one Ive come across when it comes to what I was looking for in particular (use the Document, Black/White filter), and it basically comes out super crisp and without any background jargon. I use the OCR in my Adobe Acrobat, so I cant speak for how that in particular compares, but it does work. It just takes about 15-20 secs. Other than that, the scanners the best one so far.

Mister0090 about Clear Scan: Doc Scanner App