SAFR Actions gives the option of generating an event either at the start or at the end of an event.  While normally the preference is to have an notification generated as early as possible, this can cause issues where a face that is initially determined to be unrecognizable or stranger, later is updated to a known person once sufficient information is made available to SAF (i.e. face gets larger, person looks more towards the camera, etc).  This results in a notification reporting someone as a stranger or unrecognized when actually they are known and may have been classified as a threat or concern.

To avoid this issue, one can use Event Delay setting.  This setting causes SAFR to wait to generate an event until either a sufficient time passes or the person has left the view.  Setting Event Delay to a sufficiently large value will ensure that SAFR is given time to match a face.  This reduces the frequency of false non-matches.

Event delay is set on one of two ways.

For Camera Analyzer, use the Preferences Dialog:

If running SAFR as a background Windows Service in the Video Feeds window, use the following property to set Reporting Delay:

With Event Delay set to 20 seconds, the following behavior is observed:

• Known person that is initially far away shows as unrecognizable (no event generated yet) and then if that person moves closer and get recognized, overlay changes to known person.  

  • If that person either wait until 20 seconds elapses or leave view before 20 sec and event generated is known person.

• If a face starts out unrecognizable and stay that way, then either at 20 sec or when leaving view, unrecognizable event generated in event viewer.  

  • Note: Do not set unrecognizable event delay to 0 seconds.  Use a value of 0.01 to avoid a defect that results in unrecognizable becoming 1.5 seconds.

• Same behavior results for a stranger (not in datbase) as for the known person described above..

Following is a video demonstrating behavior for a known and stranger: