Good news! rEmotion 2 is now shipped with the Linux library that can be used to interact with the module from your Raspberry Pi or any other Linux device!
The update is available in the repository:
Look at the example application that constantly writes frames to the img.jpg file, moves the head, and changes facial expressions!
While working on this update I realized, that my initial web camera was not suitable for the project, so the updated assembly documentation is available here (no mechanical changes needed):