InstituteforPatternRecognitionandArtificialIntelligence;
StateKeyLaboratoryforImageProcessingandIntelligentControl;
HuazhongUniversityofScienceandTechnology;
Wuhan430074;
P.R.China;
DepartmentofElectronicScienceandTechnology;
HuazhongUniversityofScienceandTechnology;
Wuhan430074;
P.R.China;