fix bug in scale method

modules/deeplearning/unet_l1b_l2.py

@@ -223,7 +223,7 @@ class UNET:
 
             f = self.train_label_files
             nda = np.load(f)
-            label = nda[idxs, 0, :, :]
+            label = nda[idxs, label_idx, :, :]
             label = np.expand_dims(label, axis=3)
         else:
             f = self.test_data_files