Dahua NVR52-4KS2 Series User Manual page 285

2. Click to draw the minimum size or maximum size to filter the target.
The system triggers an alarm only when the size of detected target is between the
maximum size and the minimum size.
3. Set parameters.
Parameter Description
Preset Select a preset you want to use IVS.
Name Customize the rule name.
Duration Set how long the object stays until the alarm is triggered.
You can set alarm sensitivity. The higher the value, the easier to detect
Sensitivity
crowd gathering but meanwhile the higher false alarm rate.
4. Click OK.
Step 6 Configure alarm schedule and linkage.
Figure 5-151 Crowd gathering
Table 5-38 Crowd gathering parameters
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User's Manual