Although performing OCR on text is not a new technology, performing it in the real world is much more difficult as text can be written anywhere and first you have to find it. Menglong's code is able to detect areas of text in a camera image and perform text recognition on them separately.
This is another great contribution to ROS from the GRASP Lab. For more information, please see the literate PR2 page on the ROS wiki.
"Penn Students Help Robot Grasp the Art of Reading" in Newsworks.org
This work also featured in... http://www.willowgarage.com/blog/2011/06/09/pr2-and-ros-action-penn