We present a novel calibration framework for multi-projector displays that achieves continuous geometric calibration by estimating and refining the poses of all projectors in an ongoing fashion during actual display use. Our framework provides scalability by operating as a distributed system of “intelligent” projector units: projectors augmented with rigidly-mounted cameras, and paired with dedicated computers. Each unit interacts asynchronously with its peers, leveraging their combined computational power to cooperatively estimate the poses of all of the projectors. In cases where the projection surface is static, our system is able to continuously refine all of the projector poses, even when they change simultaneously.