CN201349301Y

CN201349301Y - Video transmission system for railway field video monitoring

Info

Publication number: CN201349301Y
Application number: CN 200820144597
Authority: CN
Inventors: 宋维
Original assignee: Tianjin Normal University
Current assignee: Tianjin Normal University
Priority date: 2008-12-19
Filing date: 2008-12-19
Publication date: 2009-11-18
Anticipated expiration: 2018-12-19

Abstract

The utility model discloses a multi-channel CDMA video transmission system for railway field video monitoring, which consists of a video front-end monitoring sub-system, a CDMA network and a background video processing system. The analog video signal photographed by a CCD camera is transmitted to a video decoder and a synchronous separation circuit; the video decoder conducts A/D conversion to the video, and then transmits the video signal and the line-field synchronous signal after the A/D conversion to a JPEG encoder; a video memory is arranged between the JPEG encoder and an ARM processor to match with the speed; the ARM processor is further provided with a large-capacity Flash memory to store the compressed images; and the ARM processor connects a CDMA communication module 1 to a CDMA communication n. Consequently, the image quality can be adjusted; and the video transmission system for railway field video monitoring is applicable to the occasions with quite higher real-time requirement.

Description

The Video transmission system of monitoring railway field video

Technical field

The utility model belongs to the technical field of applying electronic product, designs a kind of multipath CDMA video transmission system of monitoring railway field video.

Background technology:

The railway mileage line is longer, in order to safeguard the safe operation of railway, need carry out the continuous videos monitoring to many kinds of emphasis locations and zone.In the emphasis location and zone that these need be monitored, there is considerable part to be in the incomplete places of wire communication facility such as mountain area, plateau, the transmission of using wired mode to carry out video data can not realize.

For these locations and the general employing in zone " wireless video communication ", in the selection of mode, mainly be to utilize GSM (Global System for Mobile communication, global system for mobile communications) and CDMA (Code Division Multiple Access, code division multiple access) network, its reason are that its network coverage face is wider.Compare GSM and CDMA, under existing technical conditions, the communication bandwidth of cdma network is higher than the GSM network, so generally adopt the CDMA video communications system on railway.

Existing C DMA video communications system all adopts single CDMA module, owing to be subjected to the restriction of CDMA transmission bandwidth, must compress significantly and reduce video size video, on compress mode, adopt MPEG (Moving Pictures Expert Group, Motion Picture Experts Group) compress mode (contain MPEG-I, MPEG-II, MPEG-IV and H.264), the common feature of these compress modes is to have frame-to-frame correlation (exist between frame and the frame and get in touch).Exactly because also this reason must adopt single CDMA module so its transmission is gone up.

This just causes the real-time of its video and picture quality not high, and especially in the period of network congestion, its shortcoming is more outstanding; And image is big or small and quality can not be adjusted significantly according to user intention.

The utility model content

The purpose of this utility model is the deficiency that the multipath CDMA video transmission system at existing monitoring railway field video exists, and designs a kind of multipath CDMA video transmission system and can adjust the image size significantly and quality effectively realizes the video monitoring assurance safe railway operation in railway field according to user intention.

Provide a kind of multichannel (Code Division Multiple Access that is used for monitoring railway field video in order to reach the purpose of this utility model, code division multiple access) Video transmission system, it is made up of video front Monitor And Control Subsystem, cdma network and backstage processing system for video structurally as shown in Figure 1.The block diagram of front end Monitor And Control Subsystem comprises compositions such as Video Decoder, JPEG (Joint Photographic Experts Group, JPEG (joint photographic experts group)) encoder and multichannel communication module as shown in Figure 2.The analog video signal of being taken by the CCD camera imports Video Decoder and synchronizing separator circuit into, Video Decoder carries out the A/D conversion to video, then vision signal after the A/D conversion and row field sync signal are sent, video memory is set in order to matching speed between jpeg coder and the arm processor, video memory connects CPLD (complex programmable sieve is collected device), arm processor is furnished with the image that big capacity Flash memory is crossed in order to store compressed in addition, and arm processor connects CDMA communication module 1 to CDMA module n.Video image imports video server into by cdma network, and video server is responsible for the reorganization and the decompression of image.

Advantage of the present utility model: the utility model adopts MJPEG (Motion-JPEG, motion JPEG, being continuous JPEG code stream) technology generation is for MPEG (the Moving PicturesExpert Group that generally uses now, Motion Picture Experts Group) technology, can carry out framing code to the image that captures, idle discrimination algorithm is installed selects suitable CDMA module that image is sent to video server, finish the recombination of image by video server.So promptly can adjust the bandwidth of video transmission by adjusting the CDMA module number of connecting system; The big I of image is adjusted according to user's needs, after volume of transmitted data increases, only needs to increase the CDMA module number and gets final product; Picture quality can be adjusted; But the occasion that requirement of real time is higher

Description of drawings

Fig. 1 is the block diagram of system of the present utility model.

Fig. 2 is its composition frame chart of multichannel video monitoring module of the utility model embodiment.

Embodiment

Fig. 1 is the block diagram of system of the present utility model.Fig. 2 is its composition frame chart of multichannel video monitoring module of the utility model embodiment.Describe solution of the present utility model in detail below in conjunction with accompanying drawing.The utility model adopts the multichannel module to solve the problem of video bandwidth, and (MJPEG is called the Motion-JPEG compress mode, and its characteristics are not have frame-to-frame correlation to change the front end compress mode into MJPEG.System is made up of front end Monitor And Control Subsystem and backstage processing system for video two parts.

Front end Monitor And Control Subsystem composition frame chart as shown in Figure 2, analog video signal imports Video Decoder into and does not separate circuit with the step, Video Decoder carries out the A/D conversion to video, synchronizing separator circuit is used to propose the row field sync signal; Send jpeg coder with vision signal behind the A/D and row field sync signal then, video memory is used for the buffer memory effect between jpeg coder and the arm processor, in order to carry out speeds match.Arm processor is furnished with big capacity Flash (lightning) memory in addition, be used for and server between carry out metadata cache, with matching speed, and keep video image at the scene.The video that arm processor imports jpeg coder into is that unit encodes with the frame, and be in charge of the CDMA communication module of access, arm processor adopts idle discrimination algorithm, the CDMA module of frame of video by the free time sent to video server, video server carries out frame of video rearrangement, playback real-time video according to the frame number of every frame.

Adopt this scheme can increase system cost and operation cost, for the railway system, its primary and foremost purpose is the video monitoring that solves important events, obtain the real-time video of high-quality, to improve the safety of the railway system, insensitive to the system cost and the operation cost that increase, so can promote in railway system's large tracts of land.

Claims

1, a kind of Video transmission system of monitoring railway field video, it is by the video front Monitor And Control Subsystem, cdma network and backstage processing system for video are formed, the front end Monitor And Control Subsystem, comprise Video Decoder, compositions such as jpeg coder and multichannel communication module, it is characterized in that importing Video Decoder and synchronizing separator circuit into by the analog video signal that the CCD camera is taken, Video Decoder carries out the A/D conversion to video, send jpeg coder with vision signal after the A/D conversion and row field sync signal then, between jpeg coder and the arm processor video memory is set, video memory connects CPLD, arm processor is furnished with the image that big capacity Flash memory is crossed in order to store compressed in addition, and arm processor connects CDMA communication module 1 to CDMA module n.