diff --git a/README.md b/README.md
index f5512f9..f0b32f0 100644
--- a/README.md
+++ b/README.md
@@ -25,7 +25,7 @@ git clone https://github.com/NathanUA/U-2-Net.git
```
python u2net_portrait_composite.py -s 20 -a 0.5
```
-,where ``-s`` indicates the sigmoid of gaussian function for blurring the orignal image and ``-a`` denotes the alpha weights of the orignal image when fusing them.
+,where ``-s`` indicates the sigma of gaussian function for blurring the orignal image and ``-a`` denotes the alpha weights of the orignal image when fusing them.
