Digits-ocr is a project mainly written in RUBY and R, it's free.
sudo apt-get install libcv2.1 libcvaux2.1 libhighgui2.1 opencv-doc libcv-dev libcvaux-dev libhighgui-dev
(cd /usr/local/include && sudo ln -s /usr/include/opencv .)
git clone https://github.com/ser1zw/ruby-opencv.git cd ruby-opencv git checkout origin/OpenCV_2.1 ruby ext/extconf.rb make