[Ling, Xiaohui;Dai, Zhiping;Wang, Youwen;Chen, Liezun] Hengyang Normal Univ, Coll Phys & Elect Engn, Hunan Prov Key Lab Intelligent Informat Proc & Ap, Hengyang 421002, Peoples R China.^[Yi, Xunong] Hubei Engn Univ, Sch Phys & Elect Informat Engn, Xiaogan 432000, Peoples R China.