.. _settings:

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

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

* generic confidence threshold for face verification 
* confidence threshold for 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 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 0.745. If necessary, you can change the generic threshold. 

.. 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.

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

.. include:: /_inclusions/threshold_important.rst


Confidence Threshold for Episodes
=========================================

To construct an :ref:`episode <episodes>`, the system searches the biometric database for recent events with similar faces with a pre-defined similarity threshold. The default threshold is set to 0.689, which is considered as optimum. 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 purging old events and related episodes from the database on a regular basis. You can purge matched and unmatched events/episodes on different schedules, as well as purge only full frames for matched and unmatched events/episodes.