1. China Three Gorges University,Hubei Key Laboratory of Intelligent Vision Based Monitoring for Hydroelectric Engineering,Yichang,China
2. Northwestern Polytechnical University,School of Computer Science,Xi’an,China
3. South China University of Technology,School of Electronics and Information Engineering,Guangzhou,China
4. The University of British Columbia,Department of Electrical and Computer Engineering,Vancouver,BC,Canada,V6T1Z4