What the meaning of self._check_centers in preprocess for halpe dataset?

[Matthew-CQ]

Hi, could u please explain the preprocess code meaning? https://github.com/MVIG-SJTU/AlphaPose/blob/c60106d19afb443e964df6f06ed1842962f5f1f7/alphapose/datasets/halpe_coco_wholebody_136.py#L155

             if self._check_centers and self._train:
                bbox_center, bbox_area = self._get_box_center_area((xmin, ymin, xmax, ymax))
                kp_center, num_vis = self._get_keypoints_center_count(joints_3d)
                ks = np.exp(-2 * np.sum(np.square(bbox_center - kp_center)) / bbox_area)
                if (num_vis / 80.0 + 47 / 80.0) > ks:
                    continue