Figure 3.

Use of CNN as a feature extractor.¹⁹⁶ (a) Each ROI is sent through AlexNet and the outputs from each layer are preprocessed to be used as sets of features for an SVM. The filtered image outputs from some of the layers can be seen in the left column. The numbers in parentheses for the center column denote the dimensionality of the outputs from each layer. The numbers in parentheses for the right column denote the length of the feature vector per ROI used as an input for the SVM after zero‐variance removal. (b) Performance in terms of area under the receiver operating characteristic curve for classifiers based on features from each layer of AlexNet in the task of distinguishing between malignant and benign breast tumors.