A system for monitoring images and sound, with voIP technology applied to the monitoring of sound

摘要

NTT's telecom buildings are equipped with emergency generators. These generators must be tested about four times a year, to ensure that they can start. They can be tested from a remote monitoring office, but are usually tested on the spot, so that the inspector can listen to the machinery and confirm that it is in good order, and visually inspect the surrounding area. NTT Power and Building Facilities (NTT-F), the firm that is responsible for the maintenance of NTT's many generators, has developed equipment so that the operational condition of the generators can be remotely monitored by using images and sound. The equipment reduces the need for on the spot inspection. In 1998, we created a low cost system by using an internet camera to place images on the world-wide web, and an analog loudspeaker phone to allow the sound to be monitored over the telephone lines. We applied this system to maintaining the operational condition of NTT's CGS (Co-Generation System). We have improved the system in a number of ways since then, for example in terms of the precision of the image. Voice-over-Internet Protocol (VoIP) technology has recently been applied to the audio monitoring as a cost reduction measure. This thesis is about the construction, performance, characteristics, and so on, of the monitoring system.