I have a pdf file (500 pages) with a lot of images ( black and white). However, the text is blurred and although it is readable, it's really a pain ( maybe hardcopy was scanned poorly, not sure on that).
Is there some way I can 'clean' the pdf file ? I can manage with diagrams in the present quality because they are big and so I'm ok. But the text is not manageable. So ideally, I would like to create a replica but with good text quality.
I can't really use some convertors because there are images in the pdf file (and that too plenty in no).
Using ubuntu 14.04.
I'm not a dev. Just a normal user.
Update:
I would again like to emphasise that pdf file has a lot of images as well, and text is blurred badly. Unfortunately, gscan2pdf didn't work at all.