diff --git a/codes/models/feature_model.py b/codes/models/feature_model.py
index b957612d..dc9d9dd5 100644
--- a/codes/models/feature_model.py
+++ b/codes/models/feature_model.py
@@ -72,12 +72,7 @@ class FeatureModel(BaseModel):
 
     def optimize_parameters(self, step):
         self.optimizer_G.zero_grad()
-
-        # grey out the LR image but keep 3 channels.
-        lr = torch.mean(self.real_H, dim=1, keepdim=True)
-        lr = lr.repeat(1, 3, 1, 1)
-
-        self.fake_H = self.fea_train(lr, interpolate_factor=1)
+        self.fake_H = self.fea_train(self.var_L, interpolate_factor=2)
         ref_H = self.net_ref(self.real_H)
         l_fea = self.cri_fea(self.fake_H, ref_H)
         l_fea.backward()