Person_Reidentification.md

Person Re-identification

Nuitrack is now able to recognize the same users if they left the frame and returned back in a single runtime session.

Disclaimer:
For this feature to work Nuitrack SDK uses facial/body features to be able to recognize person on reappearance.
This data is processed in RAM only through a single runtime session and isn't kept / stored / transmitted anyhow anywhere.

Supported platforms

• Linux x64
• Windows x64/x86

Try out Re-identification feature

To try the person re-identification:

• launch the Nuitrack application
• make sure that the Reidentification checkbox is checked
• start visualization via Try Nuitrack! button

You will see unique person identifier next to person skeleton, as well as time of first appearance and number of seconds spent in a frame.

Getting Re-identification data using SDK

Follow these steps to get Re-identification data from Nuitrack.

1. Enable Re-identification feature after initializing Nuitrack:

   Nuitrack::init();
   Nuitrack::setConfigValue("Reidentification.ToUse", "true");

2. Create SkeletonTracker module, connect it to the callback function and start Nuitrack:

   void onSkeletonUpdate(SkeletonData::Ptr userSkeletons) { /* your SkeletonData processing */ }
   
   ...
   
   auto skeletonTracker = SkeletonTracker::create();
   skeletonTracker->connectOnUpdate(onSkeletonUpdate);
   Nuitrack::run();

3. After you run Nuitrack you can start getting it's data in JSON format like this:

   while (true)
   {
       Nuitrack::waitUpdate(skeletonTracker);
       auto jsonData = Nuitrack::getInstancesJson();
   }

   Example of JSON file:

   {
       "Timestamp": "1659084464875886",
       "Instances": [
           {
               "id": "1",
               "class": "human",
               "uuid": "2a6de0bd-5ed8-4b57-aedb-f38135f87c14"
           }
       ]
   }

   Note:

   • id from the JSON above matches with id provided by UserTracker and SkeletonTracker
   • uuid is a unique user identifier

4. Before exiting your program don't forget to release Nuitrack:

   Nuitrack::release();