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Object presence change

Object presence change detects transitions in object presence within a specified region and time window. The user can define a time window (e.g., 10 seconds), an object type (e.g., person, car), and a Region of Interest (ROI).

Within the selected time window, the system analyzes whether there is a change in the presence of the specified object type. For example, if no person is detected during the first half of the window but one appears in the second half, the system registers a detection with an "appeared" attribute. Similarly, if an object disappears, it is marked as "disappeared".

By aggregating multiple such detections within the configured time window, the overall accuracy improves significantly - the longer the time window, the more frames are analysed. This type of query is ideal for use cases where some latency is acceptable: a common example is monitoring parking areas — the departure and arrival of cars (or even airplanes) can be detected with high precision.

Use case examples

  • Monitoring parking areas for the arrival and departure of vehicles.
  • Detecting the presence or absence of people in areas of interest, such as entrances or exits.
  • Tracking object movements in controlled environments, such as warehouses or factories.

  • Go to Video Search Advanced Search to set up a Search for presence with absence events.

  • Go to Live Rules New Rule to set up a real-time detection of presence with absence events with alarm integration.

Select Source

Select the video you want to run the Search on from the left sidebar. The thumbnail image of the chosen video is displayed here.

Time interval Advanced Search only

Time interval

Select a time frame for the analytics to run.

  • Entire video: Run the Search on the entire video duration, from the start timestamp to the end timestamp (set during video registration).
  • Custom range: You can select a custom start and end date and time to run the Search on. Type the desired date and time or select them by clicking the calendar icon.

Object Filter

Object filter

Select one or multiple object types you want to search for.

  • Sensitivity (Medium by default): The sensitivity level of the Search. The higher the sensitivity, the more likely it is to detect objects, but it may also result in more false positives.

Ticking the Expert Settings box will open additional configuration options for the Search, such as more object types to choose from.

Algorithm

Object filter

Select one or multiple object types you want to search for.

  • Detection zone: Draw a polygon on the video frame to define the area where the objects will be detected. Left-click on the video frame to draw a polygon. Left-click again on the video frame to keep adding points to the polygon; double-click to finish drawing.

Drawing ROI is only supported on videos with a fixed camera angle (i.e. not on moving cameras). PTZ cameras are supported only in fixed position.

Note that currently only one ROI can be drawn.

  • Window length (in seconds, 2 by default): The length of the time window during which the system analyzes changes in object presence. A longer window allows for more frames to be analyzed, improving accuracy.

  • Generate event when: Select whether an event should be generated when an object appears, disappears, or both.

Alarm integration Live Rules only

You can choose to integrate the Search with an alarm system.; whenever a stopped object is detected, an alarm will be triggered in the integrated system.

Results

All done - Clicking Search will immediately start the analysis and opens the Search Results screen.

Live Rules will produce real-time detections , and the results will be displayed in the Alarms screen. If an alarm integration is set up, an alarm will also be triggered in the integrated system.