A Similar, but Different Question
(I was considering making a new topic, but decided to post here instead.)
I originally had a 12-page journal article, separated into 12 gif images. Using Automator's "New PDF from Images" command, I turned them into a single, 12-page pdf file. (I mention this, in case it's better to OCR on the original GIF pages.)
I've found a few OCR programs, but what they do is take the words from the article, and output them into a text file - but that's not what I want.
Specifically, my problem is that Preview will not let me highlight, underline, or otherwise "markup" any of the lines of text in the article. I want Preview to somehow recognize the words and lines of text in this article, so that I can highlight them. (mkrishnan, I gather that this is the same thing as "the ability to copy / paste / search the text," as you mention.)
Here's a big limitation: I would like to spend no money to do this. This means that I won't buy a Canoscan scanner just to do this...unless it's possible to download the software by itself for free, and have it perform OCR on the GIF or PDF files I give it. But if the only software you can think of costs money, then please tell me anyway; if it's not too expensive, I just might buy it someday.
Granted, this problem is by no means essential to my livelihood: I realize that I could just markup the text using 'Notes' and 'Ovals or Rectangles' instead of Highlighting. Highlighting is just really convenient.
So, any ideas would be appreciated.