.. _deduplication:

Deduplicate Events
=========================

.. rubric:: In this section:

.. contents::
   :local:

Consider enabling Deduplication to exclude coinciding facial recognition events within one camera group.


Enable Deduplication
--------------------------

To enable event deduplication, do the following:

#. Enable the offline mode of video face detection for each camera in the group. See :ref:`add-camera` for details.
#. Navigate to the :guilabel:`Preferences` tab. Click :guilabel:`Camera Groups`.
#. Open the camera group settings.
#. Check :guilabel:`Deduplicate Events` and specify the deduplication interval in seconds.

How It Works
---------------------

The deduplication algorithm works as follows:

#. In the offline mode, the server receives one best face snapshot per tracking session on a camera (a tracking session continues until a face disappears from the camera field of view). 
#. If within the same camera group, there are several tracking sessions on a camera(s) within the specified deduplication interval, FindFace will handle the received snapshots in the following way:

   * If there is a match with a dossier within the preceding deduplication interval, FindFace drops a newly acquired snapshot. Otherwise, the snapshot is saved to the database.
   * For unmatched faces, when performing deduplication, FindFace considers both similarity between faces in the snapshots and face quality. FindFace drops all snapshots of similar faces within the deduplication interval unless a new face is of higher quality. This guarantees that the system deduplicates events without skipping high-quality faces, which are essential for further video analytics.