im_fname = osp.join(self.data_root, '{}.png'.format(im))
de_fname = osp.join(self.data_root, '{}_depth.npy'.format(im))
de_mask_fname = osp.join(self.data_root, '{}_depth_mask.npy'.format(im))
im = np.array(Image.open(osp.join(self.data_root, im_fname)))
on the last line the im_fname is joined twice with self.data_root