Ancient Greek OCR is easiest to use on Mac OS X with the free software VietOCR application, with the Homebrew Tesseract package. Below are step by step instructions to install and set it up, and use it, for Ancient Greek OCR.
brew install tesseractinto a terminal window and pressing Enter.
If you get an "unidentified developer" error, click OK, then go to Apple -> System Preferences -> Security & Privacy, and click "Open Anyway".
mv Downloads/grc.traineddata /usr/local/share/tessdata/
You can now open VietOCR with Ancient Greek OCR!