Fig. 9

a–r Results of sex estimation based on orientation of region partition and number of regions using KPCA. The results of KPCA-KELM are depicted in (a, d, g, j, m, p). Results of KPCA-SRC are depicted in (b, e, h, k, n, q). Results of KPCA-SVM are depicted in (c, f, i, l, o, r)