Figure 2 The multistep cascade experiment pathway of EDLC-TN. (A) The process of extracting ROI and mask. First, the boundary was cut off (a). Second, the nodule area was segregated (b). Then, the mask image of the thyroid nodule was depicted (c). Finally, ROI was segmented (d). (B) The process of classifying images by ensemble learning model. After obtaining the ROI and its corresponding mask, three classification models were trained and combined to obtain an advanced classification model. ROI was put into models and got the final classification result through the voting method.