Fig 3.

The decision surface of SVM is indicated in feature space by using HIST1 and HIST10. The upper-right part in the figure indicates that the output of the classifier is positive, and down-left part indicates that the output of the classifier is negative. The circle symbol indicates true-positive samples and plus symbol represents true-negative samples, the features of which were used to train the SVM-based classifier. This figure indicated that the high percentage of calcification and low attenuation pixels suggested that the nodule was benign.