This search type compares every recognized face with all faces in the camera database over 30 days (or for the current archive depth if it is less than 30 days) and sets the number of days over which this face was recognized by the camera. The search decides if this is a “familiar face” or a “stranger” by the specified criteria.

The POST request is used for search start (see Search request), search type is stranger, request body is empty.

The following parameters are available:

• accuracy – sets face similarity level in the range [0,1] (1 means complete match). If this parameter is not set, then the default value (0.9) is in use. If the compared face was in the camera field of view on a specific day and it was recognized with accuracy that is not less than specified one, then this face is considered to be present on that day. Otherwise, the algorithm considers this face was absent on that day. 
• threshold – defines the threshold value to recognize a face as a “stranger”. The value is set in the range from 0 to 1 and it defines the number of days within which the face was absent to be considered as a “stranger”: 30-30*threshold. For instance, the value 0.8 means “the required object appeared in the search area within (30 - 30 * 0.8 = 6) days”. All faces that appeared within 6 and more days will be defined as “familiar faces”, others – as “strangers”.
• op – defines search direction.
  Allowable values:
  lt – “familiar face” search (based on treshold parameter).
  gt – “stranger” search.
  
  

JSON search result looks like this:

{
   "events" : [
      {
         "rate" : 0.90591877698898315,
         "origin" : "hosts/SERVER1/DeviceIpint.2/SourceEndpoint.video:0:0",
         "position" : {
            "bottom" : 0.10694444444444445,
            "left" : 0.69687500000000002,
            "right" : 0.74687500000000007,
            "top" : 0.018055555555555554
         },
         "timestamp" : "20160914T085307.499000"
      },
      {
         "rate" : 0.90591877698898315,
         "origin" : "hosts/SERVER1/DeviceIpint.2/SourceEndpoint.video:0:0",
         "position" : {
            "bottom" : 0.10694444444444445,
            "left" : 0.69687500000000002,
            "right" : 0.74687500000000007,
            "top" : 0.018055555555555554
         },
         "timestamp" : "20160914T085830.392000"
      }
}

where

• • origin - camera channel to take analyzed video stream from.
  • timestamp - time stamp of a frame with a face detected by the detection tool.
  • rate - rate of identifying a face as a “stranger”, the value in the [0,1] range. 1 means a complete stranger.
  • position – coordinates of a frame border enclosing face on a video frame.