Real-time synchronized vision sensors over Ethernet

Abstract

A network of real-time vision sensors is described using 100baseT Ethernet. Each vision sensor comprises a camera connected to a dedicated computer to form a "vision node". Each vision node is capable of capturing and processing images and communicating the results over the network to a master computer in real-time. Deterministic and timely operation using standard Ethernet is accomplished using three basic techniques: suppressing superfluous packets; using the UDP transport protocol; and using an application layer protocol based on master/slave round-robin polling. Deterministic communications also enable the acquisition times of the cameras to be synchronized over the Ethernet network. By synchronizing the vision nodes to interleave their capture times, network contention is avoided and the effective video sample rate is increased. An analysis is also performed to determine the maximum number of vision nodes that can be supported using this technique over 100baseT Ethernet.