Design And Implementation Of The Long-distance Image Surveillance System Based On PSTN

The image surveillance system has great significance for the guaranty of industry production, life of people and social security. At present, with the development of science and technology and the improvement of living standard, the long-distance image surveillance system has been more and more applied in various fields, such as finance, banks, military affairs, post and telecommunication or other enterprises based on a vast information communication.The thesis discusses the design and realization of a long-distance image surveillance system based on PSTN, which has fully utilized existing communication resource, telephone network. It can monitor and control the locale whenever and wherever possibly, and is not restricted by time and place. This system has the advantage of smallness, low costs, and steady performance, which doesn't need special messengers to manage, and is suitable for various kinds of occasions with no guard. The system not only has such functions as image transmitting, long-range control, on-the-spot signal gathering, autoalarm, etc, and it can also offer the high-quality surveillance image and convenient control way.Speaking from the function, the long-distance image surveillance system can be divided into two parts. The first part is a module of signal gathering and control. It uses AT89C51 as the main processor, which includes sensor signal measure, autodial, circuit state measuring, DTMF signal decoding, and automatic control. It is used to realize on-the-spot signal gathering, autodial and giving the alarm, and long-range control. The second part is the module of image processing, which is the problem that is mainly solved by the system. The key to solve the problem is image compression, which is achieved by adopting the way in which the software and hardware are combined. In hardware, the chip of SAA7113 is used to exchange video signal input from analog image into digital image. The digital signal of image is inputted into DSP chip to be compressed after buffering. In addition, Logic...