Research And Development Of Digital Video Surveillance System Based On DirectShow

As a growing tendency of modern defence system, Video Surveillance System has charactors of visibility, convenience and abundant in content. Many advantaged technologies are applicated in digital video surveillance system including multimedia, network transmission and digital video imagery processing technology etc. That made the system according with the digital, network and intelligent developing trend of current information society. So it can be applied to various fields.To detect the moving objects from raw video is the base of implementing intelligent surveillance system. A frame differencing algorithm is accomplished to detect moving objects under the stationary background with single camera after researching in detail three conventional approaches of moving object detection in this thesis. Through using this approach, not only the sensitive scene can be recorded, but also the storage and the labor of monitoring can be saved simultaneously.This thesis presents the current key technologies of Digital Video Surveillance System firstly, and then introduces the technical routine that has been choiced. Finally, the system is designed and built, which be consisted of the client and server side including the module of video data capture, moving object detection, video data compressor, net transmission and video data receiver, decoder and playback. TCP is used for the control command that need the high reliability, and IP Multicast based on UDP for the transmission of video data. In the server, the captured video data is displayed on the screen, and the moving object is detected simultaneously, the data is encoded by MPEG-4 compression standard, then the compressed data will be multicasted to the client based on RTP. The client is responsible for receiving, decoding and playing the video imagery. Bi-buffer technology is achieved in receiving the RTP packet to alleviate the delay of network. The technology of Multithread is used in both sender side and receiver side.The digital video surveillance system which is described in the thesis is possessed of hardware-independent generality for the using of DirectShow Framework. Further, the application of moving object detection lays the foundation for the expandability and improvement of the system function.