遥测站采用HTTP协议传输图片的应用研究

Application research on HTTP protocol based image transmission in telemetry station

针对遥测站采用水利行业规约传输图片效率较低等问题,为在水文自动测报系统中基于移动通信网络或者有线嵌入式以太网灵活、高效地传输图片,介绍遥测站的数据特点、拍摄图片的常用压缩格式和传输方式,研究在遥测终端机中应用HTTP协议传输图片的过程。采用HTTP协议,将遥测终端机作为客户端与服务器建立起TCP连接,应用层按照HTTP协议将要发送的信息组织成请求报文进行发送,不考虑数据分包、失败重传和数据校验机制,由下层TCP/IP协议负责数据可靠传输,服务器将接收的二进制流数据保存成图片。相较于2种水利行业规约,采用HTTP协议传输图片,时效性更强,可以兼容很多互联网的通信应用,方便与各种服务接口对接。

In view of the problems of low efficiency of image transmission by using water conservancy industry protocol in telemetry station,this paper introduces the data characteristics,images common compression format and transmission mode taken by telemetry station,and studies the process of transmitting images by using HTTP protocol in telemetry terminal,in order to flexibly and efficiently transmit images based on mobile communication network or wired embedded Ethernet in automatic hydrological monitoring and reporting system.Using HTTP protocol,the telemetry terminal is used as the client to establish a TCP connection with the server.Application layer organizes the information to be sent into request messages according to HTTP protocol.Regardless of data subcontracting,failure retransmission or data verification mechanism,the lower TCP/IP protocol is responsible for reliable data transmission,the server saves the received binary stream data as a picture.Compared with the two water conservancy industry protocols,HTTP protocol is used to transmit pictures,which has stronger timeliness,can be compatible with many Internet communication applications,and is convenient to connect with various service interfaces.