I am looking for software that helps me to transcribe scanned documents. I am aware of two solutions, GenScriber (Windows, Linux) and Transcript (Windows). Is there something like that for Mac OS X? It should offer a split screen view (source and input area), basic image manipulating options (e.g. for enhanced contrast and rotating), and CSV export.
There aren't any that are native to the Mac. But there are a couple of online ones that may work for you.
Scripto is a free open source tool written in PHP for enabling community transcription of document and multimedia files. It runs under WordPress, Drupal or Omeka (3 content management systems).
FromThePage An free open source online tool written in Ruby that allows volunteers to collaborate to transcribe handwritten documents.
Both have development areas at github. I believe they both have split screen views. I can't tell you about the other options.
The other thing you can do is use a Windows emulator on your Mac, and then run GenScriber or Transcript. For example check out CrossOver, Parallels, Guest PC or VMware Fusion. All are relatively inexpensive.
I can provide you with a GenScriber version that will run in X11.
If you want to give it a try, I would be willing to make any adjustments needed to ensure success.