User Manual
Network Video Recorder User Manual   
UM NVR v4.xx 111717NA  135 
Time Threshold: The time of the objects removed from the region. If the value is 10, alarm 
will be triggered after the object disappears from the region for 10s. Its range is 
[5s-20s]. 
Sensitivity: The similarity of the background image. If the sensitivity is high, a very small 
object taken from the region will trigger the alarm. 
3)  Click Draw Region and draw a quadrilateral in the preview window by specifying 
four vertices of the detection region. 
Step 7 Set the arming schedule. Refer to Chapter 12.1 Configuring Arming Schedule.     
Step 8 Set the linkage actions. Refer to Chapter 12.2 Configuring Alarm Linkage Actions. 
Step 9 Click Apply.   
13.9 Audio Exception Detection   
Purpose 
Audio exception detection detects abnormal sounds in the surveillance scene such as a 
sudden increase/decrease in sound intensity. 
Step 1 Go to System > Event > Smart Event. 
Step 2 Click Audio Exception. 
Figure 13-9 Audio Exception Detection 
Step 3 Select a camera to configure. 
Step 4 Optionally, check Save VCA Picture to save the captured audio exception detection 
pictures. 
Step 5 Set the detection rules: 










