Update README.md

Author: jhan15

.DS_Store

@@ -54,7 +54,7 @@ Detect hands on streams, it draws the landmarks on detected hands and returns ha
 Detect hand gestures on streams, it can detect a series of pre-defined hand gestures, including Chinese number 1 - 10, 'OK', 'Thumbs-up', 'Thumbs-down', 'Rock', 'Claw', 'C shape', 'O shape', 'Pinch'.
 
 ### Volume controller
-Control volume using hand gestures. It's a possible application in areas like smart home and in-cabin interaction. Hand gestures can be used for activation, deactivation, and control.
+Control volume using hand gestures. It's a possible application in areas like smart home and in-cabin interaction. Hand gestures can be used for activation, deactivation, and control. In this case, we use 'Pinch' as activation and control gesture and 'C shape' as deactivation gesture.
 
 #### Continuous control