Visual tracking for mobile optical wireless communications.

Acquisition, tracking, and pointing (ATP) mechanisms are generally adopted for optical wireless communications (OWCs) to maintain a strict alignment state for reliable communication. ATP mechanisms conventionally employ beacon lights to determine the orientation of the remote optical terminal. They typically cannot maintain a steady alignment under mobile conditions. A novel visual tracking approach is proposed to address this issue by establishing a shape beacon at the OWC terminals. The shape beacon can be sensed from virtually all directions with a camera; hence, visual tracking is an acceptable ATP solution for mobile OWCs. Results of numeric analysis indicate that visual tracking is suitable for mobile OWCs as well as conventional OWCs with acceptable accuracy. Experiments were performed to demonstrate the visual tracking procedures using the vehicle itself as the shape beacon.