Camera-based video synchronization for a federation of mobile projectors

Ultra-portable projectors, called pico projectors, are now being embedded in mobile devices like cell-phones. Such mobile devices are projected to be the primary device to be used by younger people for ubiquitous sharing of all possible media initiating novel social interaction paradigms. Yet, the pico-projectors offer a much lower resolution and brightness than a standard projector. However, images displayed from multiple such mobile devices can be tiled to create a dramatically improved display in both brightness and resolution. This will allow multiple users to view and share media at a much higher quality. In this paper, we present a camera-based video synchronization algorithm that allows a federation of projection-enabled mobile devices to collaboratively present a synchronized video stream, though only a smaller part of the video comes from each device. Since, the synchronization does not use any wireless network infrastructure, it is independent of network congestion and connectivity. We combined our method with existing distributed registration techniques to demonstrate a synchronized video stream for a federation of four projectors arranged in a 2 × 2 array. To the best of our knowledge, this is the first time that a camera-based technique has been used to mitigate network uncertainties to achieve accurate video synchronization across multiple devices.