【作者】 张睿萍；

【导师】 徐东平；

【作者基本信息】 武汉理工大学 ， 计算机应用技术， 2008， 硕士

【摘要】 视频监控系统以其直观、方便、信息内容丰富而成为现代安防系统发展的主流。其中,数字视频监控系统采用了多媒体技术、网络传输技术及数字视频图像处理技术等众多新技术,符合当前信息社会数字化、网络化和智能化的发展趋势,被广泛应用于各行各业。对视频图像进行运动目标检测是实现数字视频监控系统智能化的基础。本文在详细分析、研究了目前常用的运动目标检测方法和技术实现后,针对静止背景下的单摄像头监控,采用相邻帧差法对视频监控图像进行运动检测,在保证记录到有事件发生的关键场景的同时,有效提高了存储空间的利用率及事后检索的方便性,从而降低了监控人员的工作强度。本文首先介绍了数字视频监控系统中所采用的关键技术,然后详细分析了系统所要实现的目标,从而确定了系统实现要采用的技术路线。最终设计并实现了一个C/S通信模式下的数字视频监控系统,由视频采集、运动检测、视频处理、网络传输及视频的接收、播放模块组成。系统中对于要求高可靠性的控制指令,选用TCP协议;而对实时性要求高的视频流数据的通信则选用基于UDP协议的IP组播实现。系统在现场端利用DirectShow技术实现对所捕获视频的播放,视频数据经运动检测、MPEG-4压缩处理后,利用位于UDP协议之上的RTP/RTCP协议将编码后的视频流发送到远程接收端。接收端负责接收和解码播放发送来的视频数据,并在接收过程中采用双缓冲技术来缓解网络延迟和抖动带来的影响。视频数据发送端和接收端均采用多线程技术实现。论文所述的系统,采用DirectShow技术,实现对所捕获视频的播放,因此使得系统具有与底层硬件无关的通用性,而运动目标检测技术的加入,为系统功能柔性扩充和完善奠定了极为重要的基础。更多还原

【Abstract】 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.更多还原