Digital Video Recorder User Manual 
 
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The image blur caused by defocus of the lens can be detected, and some certain actions can be 
taken when the alarm is triggered. 
   
 
Please refer to the Chapter 10.1 Face Detection for operating steps to configure the defocus 
detection.   
 
The Sensitivity in the Rule Settings ranges from 1 to 100, and the higher the value is, the 
more easily the defocus image can trigger the alarm.   
10.15 Sudden Scene Change 
Purpose   
Scene change detection function detects the change of surveillance environment affected by the 
external factors; such as the intentional rotation of the camera and some certain actions can be 
taken when the alarm is triggered. 
   
 
Please refer to the Chapter 10.1 Face Detection for operating steps to configure the scene 
change detection.   
 
The Sensitivity in the Rule Settings ranges from 1 to 100, and the higher the value is, the 
more easily the change of scene can trigger the alarm. 
 
For the analog cameras, the line crossing detection and intrusion detection conflict with 
other VCA detection such as sudden scene change detection, face detection and vehicle 
detection. You can only enable one function. If you have enabled line crossing detection or 
intrusion detection, when you enable sudden scene change detection and apply the 
settings, the following attention box pops up to remind you there is no enough resource 
and ask you to disable the enabled VCA type(s) of the selected channel(s).   
 
Figure 10-11 Disable Other VCA Type(s) 
10.16 PIR Alarm 
Purpose 
A PIR (Passive Infrared) alarm is triggered when an intruder moves within the detector's field of 
view. The heat energy dissipated by a person, or any other warm blooded creature such as dogs, 
cats, etc., can be detected.