code: def skymask_refinement(self, G_pred, img):
      r, eps = 20, 0.01
      refined_skymask = guidedfilter(
          img[:, :, 2], G_pred[:, :, 0], r, eps
      )
  
      refined_skymask = np.stack(
          [refined_skymask, refined_skymask, refined_skymask], axis=-1
      )
  
      return np.clip(refined_skymask, a_min=0, a_max=1)
  
file_path: PaddleHub/modules/video/Video_editing/SkyAR/skybox.py
imports: import cv2
  import numpy
  from .rain import Rain
  from .utils import build_transformation_matrix, update_transformation_matrix, estimate_partial_transform, removeOutliers, guidedfilter
label_desc: Use image node_id 4 for calling the SkyBox obj's underlying member method code with example usage: obj.skymask_refinement(G_pred, img) and returns: np