Table 1: Learning time (sec) for proposed and comparison methods.

Training stageTesting stage

KPCA1.067 ± 0.030.203 ± 0.006
IKPCA-RS0.201 ± 0.00320.007 ± 0.0003
INKPCA0.145 ± 0.00410.201 ± 0.004
TP-IKPCA0.087 ± 0.00260.004 ± 0.0002
NoticeThe training number N=500 and the basis number r=9 in TP-IKPCA.