Battle of Romalia is an audience-interaction game created for Building Virtual Worlds Fall 2011, Round 5. The purpose of this round was to create a spectacle. So my team decided to create what we imagined to be an epic defend-the-castle-against-the-orcs scenario replete with catapults that synchronised with the virtual catapults on the screen.
My role was to program the audience interaction and integrate that into Unity3D. Our idea was to give every member of the audience a sword and a shield and have them raise the appropriate object for attacking or defending. The strength of the attack or defence would be dictated by how many members of the audience raised their objects at the appropriate moment. The story was driven by an actor acting as the general of the troops comprised of the audience members.
I wrote the color detection module using OpenCV and used the area of the blobs as a metric of the strength of attack or defence. This was sent back into Unity over TCP. You can find the module on Github here.