Investigation Of Key Technologies In Video Security Transmission Based On WSN

The wireless sensor network is developing rapidly. And the wireless channel is a kind of time-varying random channel. So, effective routing mechanisms have received widespread attention. At the same time, the security of video transmission in wireless network mustnot be ignored. How to encrypt the streaming media to send effectively is becoming a key technology. This thesis investigates the secure transmission of video in wireless sensor network, including the routing mechanism for video transmission in WSN and the encryption algorithm for video signal. This thesis first describes the tranditional DD algorithm in the WSN for video transmission, and introducts the limited spreading range of interest and the threshold of node's rest energy to improve energy consumption and unbalanced load in DD, due to the huge volum of video data and long processing time. Thus the performance of the network is improved. Using NS2 to simulate the improved DD, compare it with traditional DD algorithm in energy consumption, time delay and packet delivery ratio. The results show that the improved DD algorithm indeed has a large surperiority in performance.For the security of the video, this thesis analyzes the features of encoding standard H.264 and proposes an encryption algorithm mixed encoding using the OFB mode of AES. In the process of encoding the video, encrypt the related coefficients to make the signal have a certain degree of confidentially. Order to improving the encryption efficiency, meeting the real-time and security requirements, the DC differential coefficients of I frames and Intra marco-blocks of P/B frames are chosen to be encrypted. The simulation results show that the proposed encryption scheme can not only meet the real-time requirement, but also protect the video data to meet the security of video transmission in wireless network with high efficiency of encryption.At the end of this thesis, the proposed encryption method is transplanted to the S3C6410 to test. The results show that the proposed encryption algorithm on the embedded platform has good performances in real-time and security.