Yinghui Quan, Shuxian Dong, Wei Feng, School of Electronic Engineering, Xidian University, China; Gabriel Dauphin, L2TI, Institut Galilée, University Paris XIII, France; Guoping Zhao, Shaan Xi Academy of Forestry, China; Yong Wang, School of Electronic Engineering, Xidian University, China; Mengdao Xing, Xidian University, China