There are various cheap (< 30 Euro) toy drones available from china. Many can be controlled via WiFi and offer a camera. In this project, I reverse-engineered the control data format to control these drones with a computer and to receive the video signal.
The SG500 and the JJRC blue crab drones are supported (they are basically the same).
The library is written in C++, but also offers Python 3 bindings. It is easy to interface with OpenCV for further image processing.
The source code and building instructions are freely available on GitHub.