Table 3: Dataset independence for pixel-based features, two datasets combined.

Classifier Trained on Tested on Error versus avg. of own testsets MNIST DIGITS USPS IBk1 eucl. MNIST-DIGITS 9.23 18.32 25.56 1.86x IBk1 eucl. MNIST-USPS 5.97 25.89 5.28 4.60x IBk1 eucl. USPS-DIGITS 22.27 22.05 6.98 1.53x IBk1 NCC MNIST-DIGITS 7.81 13.64 21.67 2.02x IBk1 NCC MNIST-USPS 4.74 24.39 4.53 5.26x IBk1 NCC USPS-DIGITS 18.95 15.53 6.98 1.68x IBk1 TD MNIST-DIGITS 4.34 11.41 10.81 1.37x IBk1 TD MNIST-USPS 2.65 16.09 3.64 5.12x IBk1 TD USPS-DIGITS 9.61 14.09 4.53 1.03x SVM linear MNIST-DIGITS 10.62 21.10 21.92 1.38x SVM linear MNIST-USPS 12.27 43.10 8.27 4.20x SVM linear USPS-DIGITS 20.37 23.83 9.67 1.22x SVM poly. MNIST-DIGITS 4.96 8.85 16.54 2.40x SVM poly. MNIST-USPS 2.66 22.16 3.89 6.77x SVM poly. USPS-DIGITS 14.56 9.97 5.23 1.92x SVM RBF MNIST-DIGITS 12.60 34.58 31.19 1.32x SVM RBF MNIST-USPS 13.60 71.66 5.63 7.45x SVM RBF USPS-DIGITS 39.89 47.38 7.03 1.47x convNN MNIST-DIGITS 3.21 4.00 6.57 1.82x convNN MNIST-USPS 1.25 11.85 2.74 5.94x convNN USPS-DIGITS 7.03 5.79 4.88 1.32x