A Heroku buildpack that installs OpenCV (currently v2.4.11) shared libs, and then exports include and lib paths to INCLUDE_PATH and LIBRARY_PATH on the build dyno, and LD_LIBRARY_PATH on the production dyno.
Simply add this Git repo to your .buildpacks file and set your Heroku config var BUILDPACK_URL to https://github.com/mojodna/heroku-buildpack-multi.git#build-env.