Fig 6. The t-SNE maps of CNN and traditional features.

From (a) to (d) are the classification and three-degree grading: area, density, location, in which the upper images are maps of FC7 features in CNN network and the lower images are typical traditional features wavelet transformation. And the blue and red dots represent samples of two different categories. (t-SNE: t-distributed stochastic neighbor embedding; CNN: convolutional neural network; FC7: the seventh fully-connected layer).