大型集装箱检测系统中的网络通讯技术

Advanced network communication technology in large container inspection system

大型集装箱检测系统是海关用于检查集装箱内装货物的新一代设备，系统的计算机硬件结构包括运行管理站、图象检查处理站、检入站、验出站、图象获取站、环境控制站、数据库站等，各站之间需要进行大量的数据信息交换。介绍系统中应用的网络通讯技术，提出并讨论比较了实现通讯的几种方案，最终选择一种具有异步机制特点、基于主控／客户模式的方案作为基本通讯模式，这种方案基于ＴＣＰ／ＩＰ和请求／应答协议，极大地增强了通讯子系统的可靠性和实时响应性。在此基础上，将分布在不同地理位置、完成各自不同功能的多个计算机工作站，采用以太网连接起来就构成一个分布式计算机网络协同处理系统。

The large container inspection system (LCIS) based on radiation imaging technology is a powerful tool for the customs to check the contents inside a large container without opening it. An image distributed network system is composed of operation manager station, image acquisition station, environment control station, inspection processing station, check in station, check out station, database station by using advanced network technology. Mass data, such as container image data, container general information, manifest scanning data, commands and status, must be on line transferred between different stations. Several communication schemes implemented are presented, discussed and compared thoroughly. At last, a scheme with asynchronous mechanism, which is called Master/Slave communication scheme with single communication channel, is chosen as the basic communication mode between different stations. This scheme is based on TCP/IP and the requirement/acknowledgment protocol, and greatly enhances the reliability and the real time response of the communication subsystem. Based on the above analysis, a distributed process system which is composed of PC and UNIX workstations has been accomplished.