| For direct and accurate observation with rich content, video surveillance technology has been one of the hottest topic in the field of information technology. Video surveillance and forensics system depends on cable networks in traditional ways with complex structure, high cost and poor flexibility. Compared with existing systems, the embedded-based wireless video surveillance and forensics system takes the advantages of low cost, stable performance, tiny shape and movable, etc., which is suitable for police in crowded situations.The system based on S3C2440 CPU chip and embedded Linux OS. Once the OS loads the USB camera driver, image acquisition program first collects video images, which will be sent via WiFi wlan card in order to connect embedded server from client, then video surveillance information is obtained by client through internet with the IP address of server.Firstly, the overall structure of the hardware is designed as well as choose the suitable devices. Software development platform is built, including cross-compiler environment building, U-Boot code porting, Linux kernel configuration, root file system creation, etc., relying on the hardware platform of the system. Then, this paper analyses the structure of USB driver and realize the load of USB camera and WiFi wlan card. On this basis, the application software is designed, the video images are captured by using V4L2 interface function in Linux kernel, and transmitted using TCP/IP protocol via socket programming under Linux OS. Next, this paper present a novel facial detection algorithm based on skin color features, which is fitting for video surveillance system. Simulations about the algorithm in Matlab shows this algorithm can match the demands of performance. Finally, integration testing of the system under B/S pattern by client through internet with the IP address of server shows the better performance comparing with traditional systems. The system proposed presents clear images with excellent performance and low delay and have good foreground of market and value of practical application. |
