PIL extraction based on the RBF kernel SVC classification. (a) The HARD detection results of the SDO/HMI magnetogram on 2023 February 1. The right two columns represent the PIL extraction steps for the active regions AR2 and AR4, respectively. Panels (b) and (c) represent the original image after threshold segmentation. Panels (d) and (e) show the extraction result without filtering. Panels (f) and (g) show the extraction result with a filter factor of 0.05.