Study Of QoS And Intelligent Analysis In Network Video Surveillance System

Network video surveillance system is one of the most important part of safe andsecurity industry which assists the public security forces to fight against crime andmaintain social stability and now is developing toward high performance, lowconsumption and intelligent video analysis. Video technologies directly affect therunning effects of the whole video surveillance system. Video process of Videosurveillance system include monitor devices’ video data collection, networktransmission and end user’s decoding and video analysis. Each part of the Videoprocess will impact the system’s performance. Therefore, in the paper, the videorelated technologies are studied and improved including hardware design，rate controlalgorithm, video transmission control technology and intelligent video analysis.A design scheme of wireless mobile monitor network video camera (NVS) and adesign scheme of H.264based NVS are given. Two schemes all are implemented byembedded design and have advantages of high performance, low energy consumptionand low cost.An improved H.264rate control based on the image complexity is proposed. InJVT, all frames are encoded in the equal way, but in video serveillance system, theinformation of scene change need to be paid more attention. More bits should beallocated when there’s t strong picture change fluctuation, and less bits should beallocated in the relatively still scenes will have a better encoding perceptual effect.The changes of image are described by complexity, so a modified H.264rate controlalgorithm is proposed which has obtained good results.An adaptive frame rate control strategy(AFRS) QoS mechanism is put forwarded.During real-time video data transmission, a new method AFRS is used. In AFRS,network bandwidth need to be detected and evaluated dynamically firstly, then datastream will be adjusted according to above evaluation result. AFRS can usereasonably network bandwidth and reduce data conflictions on the network, so thatthe monitor has a better video quality in the video serveillance system. A doublecaching mechanism(DACM) and AFRS can insure constant video quality for the enduser when wireless network sector switches or bandwidth changes greatly.An improved fast alpha blending algorithm is given. Alpha blending algorithm solves the problem that when moving object detection algorithm running, a single testfailure or strong illumination changes will lead to the failure of foreground detectionor appearance of ghost, and even extends to the whole detection region. By optimizingthe method of background modeling, an improved method is put forwarded whichreducing the running time of alpha blending algorithm. Experiment shows improvedmethod is useful especially for videos with larger resolution.The hardware design and the improved algorithms above mentioned have now beapplied to the practical projects such as Sports Event Monitoring Projects and have agood running effect.