Digital Audio and Viseo in Industrial Systems

In industrial environments such as power plants, automated factories, sewage treatment facilities, railways, etc., digital audio and video play at least three important roles:– • On-line documentation and training. Pre-stored video in documentation databases is typically viewed interactively, both during routine operation and during emergency situations. • Monitoring and surveillance. Video cameras posted around plants allow operators to keep track of security and proper operation and to provide a visual record for subsequent auditing and analysis. • Sensors for plant control. Video and image processing are being used increasingly in the automated operation of the plant itself — for example, in equipment to measure speeds, count objects, search for production flaws, detect wear of machinery, etc. In these kinds of settings, it is often desirable to integrate many different functions into the same network — for example, functions or applications with hard real-time requirements, continuous media such as audio and video, functions requiring rapid response, and traditional applications using traditional data protocols such as TCP/IP. At first glance, this may not seem too difficult if one simply dedicates a portion of total network bandwidth to the traffic with hard real-time requirements, then a portion of the remainder to audio and video, etc. However, bandwidth is only one of the resources and problems that must be considered in a complete network system. Because of the widely different communication requirements of these functions, the demands of their traffic characteristics, flow control, constraints, and performance criteria are typically more challenging than they would be in typical local area or office networks with workstations, PCs, client and server machines, etc. In this position paper, we discuss a number of issues regarding industrial networks, digital audio and video in those networks, and implications on current research directions. These are considered in the context of ATM (Asynchronous Transfer Mode) networks having speeds ranging from 100 megabits/second to one gigabit/second.