Dynamic memory: architecture for real time integration of visual perception, camera action, and network communication

In a Cooperative Distributed Vision system a group of communicating Active Vision Agents (AVA, in short, i.e. real time image processor with an active video camera and high speed network interface) cooperate to fulfil a meaningful task such as moving object tracking and dynamic scene visualization. A key issue to design and implement an AVA rests in the dynamic integration of Visual Perception, Camera Action, and Network Communication. This paper proposes a novel dynamic system architecture named Dynamic Memory Architecture, where perception, action, and communication modules share what we call the Dynamic Memory. It maintains not only temporal histories of state variables such as pan-tilt angles of the camera and the target object location but also their predicted values in the future. Perception, action, and communication modules are implemented as parallel processes which dynamically read from and write into the memory according to their own individual dynamics. The dynamic memory supports such asynchronous dynamic interactions (i.e. data exchanges between the modules) without wasting time for synchronization. This no-wait asynchronous module interaction capability greatly facilitates the implementation of real time reactive systems such as moving object tracking. Moreover, the dynamic memory supports the virtual synchronization between multiple AVAs, which facilitates the cooperative object tracking by communicating AVAs. A prototype system for real time moving object tracking demonstrated the effectiveness of the proposed idea.