We compare KCDML not only with the state-of-art methods including our current work‚ÄîCDML [38], Huang's method [43] and PCA combined with RBF (PCA-RBF) [43], but also with important baseline methods, such as PCA Kernel PCA (KPCA), LPP, Kernel LPP (KLPP) [44] and LDA.