Python3 / OpenCV 3 ( including non-free contribs)
Use this docker image in the case that you require functionality from the non-free libraries, such as SIFT / SURF / xfeatures2D etc
Since these were removed in OpenCV3 due to non-free issues.
$ cd /your-app
$ docker run -v $(pwd):/app -w /app dgtlmoon/python3-opencv3-nonfree python3 your-app.py
Tags: Available here is 3.0.0 and 3.2.0