diff --git a/src/trainer.py b/src/trainer.py
index bff6c82..21ce5e6 100644
--- a/src/trainer.py
+++ b/src/trainer.py
@@ -93,9 +93,12 @@ def supervised_training_iter(
         modnet (torch.nn.Module): instance of MODNet
         optimizer (torch.optim.Optimizer): optimizer for supervised training 
         image (torch.autograd.Variable): input RGB image
+                                         its pixel values should be normalized
         trimap (torch.autograd.Variable): trimap used to calculate the losses
-                                          NOTE: foreground=1, background=0, unknown=0.5
+                                          its pixel values can be 0, 0.5, or 1
+                                          (foreground=1, background=0, unknown=0.5)
         gt_matte (torch.autograd.Variable): ground truth alpha matte
+                                            its pixel values are between [0, 1]
         semantic_scale (float): scale of the semantic loss
                                 NOTE: please adjust according to your dataset
         detail_scale (float): scale of the detail loss
@@ -184,6 +187,7 @@ def soc_adaptation_iter(
         backup_modnet (torch.nn.Module): backup of the trained MODNet
         optimizer (torch.optim.Optimizer): optimizer for self-supervised SOC 
         image (torch.autograd.Variable): input RGB image
+                                         its pixel values should be normalized
         soc_semantic_scale (float): scale of the SOC semantic loss 
                                     NOTE: please adjust according to your dataset
         soc_detail_scale (float): scale of the SOC detail loss