Research On Video Surveillance Transmission System For Urban Rail Train

With the rapid expansion of urban rail transit system in China,more and more people choose to use urban rail transit,so the security of urban rail transit also becomes more important.As an effective means of security,video surveillance has been widely used in urban rail transit.However,most of the video surveillance systems are closed circuit TV surveillance systems,in order to make the driver to know the emergency situation in carriage,it is necessary to develop the video surveillance system of urban rail train.Based on the actual needs of project,this thesis designs a video surveillance transmission system which is based on embedded Linux,and elaborates from design requirements and system realization,system function module design,system implementation and system test.Firstly,this thesis analyses the development history and research status of video surveillance system,introduces the software platform and hardware equipment which is used in this design.And then,based on the demand of users,this thesis divides functional architecture of design into two parts:data transmission module and decoding module,and puts forward the design scheme of each module of the system.In the part of data transmission module,this thesis studies real-time streaming media transport protocol,including RTSP(Real Time Streaming Protocol)and RTP(Real-time Transport Protocol),builds equipment channel to provide data transmission,design the message passing process of RTSP and the data receiving process of RTP.In the part of decoding module,this thesis studies H.264 codec standard,builds decoding channel to connect with equipment channel,introduces the transmission sequence of NAL unit,and designs the unpacking operation in the process of H.264 decoding.In the part of system implementation,this thesis designs Executable program by using information and function of all function modules which are designed in this thesis.Finally,in the part of system test,this thesis describes the composition and the test method of test system,and verifies the feasibility and effectiveness of the program design by using the results of network packets which are caught by capture tool and the video on screen.The final test results show that the urban rail train video surveillance transmission system which is designed in this thesis realizes the function of collecting,transmitting,decoding and playing the image data,reaches the expected results,and can be applied in practice.