The Research Of Digital Video Monitor System Based On RS-485 Bus

The history of video monitor technique has experienced three generations:first generation,traditional simulation video monitor system;second generation,hard disk - video tape recorder based video monitor system and the third generation,digital video monitor system based on compressing the video image at the place of signal resource. Presently,the first generation has played an important role in the market,the second generation has just entered the market,and the third generation is in the beginning moment in its course. However,the third generation will surely replace the former two generations because it has the advantages of low cost for equipment and material,easy construction,long kinescope time,perfect image quality and rapid query rate.In this paper,we researched the digital video monitor system based on RS-485 bus,which belongs to the third generation of video monitor system. We gave emphasis to the construction of the system,the design and implementation of the serial communication protocol based on RS-485 bus,the address coding of slave machines in the system,the design of the image head of JPEG image and the exploitation of the monitor software pack.We constructed a RS-485 bus based digital video monitor system with a DSP based video-image compressing card,a RS-485 serial communication card and the monitor software pack for the master computer. We exploited the monitor software pack for the master computer using Delphi5.0 and SQL Sever7.0,it has realized the incept storage display query and return-display of the image in the monitor system,and it has met the basic need of the third generation of the video monitor system.