.. _settings:

*********************************************
General Preferences
*********************************************

The FindFace Multi general preferences determine your system functioning and resource consumption. Here they are:

* generic confidence thresholds for face, body, car recognition (subject to the enabled objects)
* confidence threshold for face recognition episodes
* thumbnail JPEG quality
* schedule for automatic events/episodes cleanup

To configure the general preferences, navigate to the :guilabel:`Preferences` tab and click :guilabel:`General`. After you are finished with adjustments, click :guilabel:`Update`. Find the detailed explanation of each setting below.

|settings_en|

.. |settings_en| image:: /_static/settings_en.png
        :scale: 40%

.. |settings_ru| image:: /_static/settings_ru.png
        :scale: 40%

.. rubric:: In this section:

.. contents::
   :local:


Generic Confidence Threshold
===============================

FindFace Multi verifies that a detected face and some face from the dossiers belong to the same person (i.e., the faces match), based on the pre-defined similarity threshold. The default threshold is set to the optimum value. If necessary, you can change it. 

.. note::
   The higher is the threshold, the less are chances that a wrong person will be positively verified, however, some valid photos may also fail verification.

The same principle applies to the body and car recognition, should you have enabled these objects. Based on the pre-defined threshold, FindFace  verifies that a detected body and a body from the dossiers belong to the same person. Likewise, a detected car matches a car from the dossiers.

.. tip::
   You can configure the confidence thresholds individually for each :ref:`camera group <camera-group>` and :ref:`watch list <create-list>`.

.. include:: /_inclusions/threshold_important.rst


Confidence Threshold for Episodes (Only Faces)
================================================

.. note::
   In the current implementation, FindFace Multi supports only episodes of face recognition events. Car and body episodes are expected in future versions.  

To construct an :ref:`episode <episodes>`, the system searches the feature vector database for recent events with similar faces with a pre-defined similarity threshold. The default threshold is set to the optimum value. If necessary, you can change this value. Be sure to consult with our technical experts prior (support@ntechlab.com).

Thumbnail JPEG Quality
============================================

Subject to JPEG quality, thumbnails may take up a significant amount of disc volume. Use the :guilabel:`General` tab to configure the parameter.  

.. _auto-cleanup:

Automatic Event And Episode Cleanup
========================================

Use the same tab to schedule automatically purging old events and related episodes from the database. For example, you can purge matched and unmatched events/episodes on different schedules and purge only full frames. You can also separately purge events with faces, cars, and bodies.