Application of fractional power polynomial kernel function to kernel direct discriminant analysis

A method of Kernel Direct Discriminant Analysis(KDDA) using fractional power polynomial kernel function is proposed,and the experiments are carried out for the variations of multi head pose and multi scale in ORL face database.The experiment results indicate that the KDDA misrecognition using fractional power polynomial kernel function is distinctly lower than that using integer power polynomial kernel function(lowers 2% when 36 features is selected).Furthermore,this advantage becomes more evident with the decreasing of the feature number.The experiments fully demonstrate the validity of KDDA using fractional power polynomial kernel function and the robustness to face illumination,head pose,facial expression and other variations.