Comparison of the spectra of (19) Fortuna, (21) Lutetia, and (279) Thule to the spectra of the simulated samples in their predicted classes. Top row: Fortuna with the samples from the C, X, and D classes. Middle row: Lutetia with the samples from the X, L, K, and S classes. Bottom row: Thule with the samples from the D, T, and X classes. The red lines are thespectra of the real asteroids, while the gray lines show the synthesized samples in the training data.