Update 'readme.md'

readme.md

@@ -140,7 +140,7 @@ python3 bounding_box.py
 ```
 
 ###Crop the mirror
-<p>The pages are now cropped, but the mirror is still visible in the middle.</p>
+<p>The pages are now cropped, but the mirror is still visible in the middle. I commented it out because if the cameras are positioned correctly there is no need for this step.</p>
 ```bash
 python3 mirror_crop.py
 ```