Face Recognition¶
Flussonic Watcher supports face detection and recognition. Face detection is finding a face on a video frame. Face recognition is matching detected faces with the person (face sample) database to answer the question "Who is it?".
Recommended video image parameters for face recognition¶
A general requirement for a video image for face recognition is the ability to recognize the face with human eyes. In other words, if you do not perceive the face in the video, then Watcher will not be able to recognize it either.
Stable face recognition is guaranteed with the following video image characteristics:
- No more than +/- 20° vertical and horizontal deviation from a right-angle (90°) view into the camera, i.e. camera should be installed at a height of no more than 2 m.
- Shutter speed not more than 1/250 to avoid noise in the frame and faces blurring.
- Frame resolution at least 1280x720 (720p). If the frame has larger resolution, it will be reduced to 720p before feeding to analytics module. Also, if camera has several streams, the closest to 720p will be used for analytics purposes.
- Bitrate at least 2 Mbps.
- The face height should be at least 1/6 of the frame height at the resolution of 1280x720. For higher resolutions, the face size should be larger in proportion to the increase in frame size. In other words, resolution should be 500 pixels per 1 m, i.e. the distance between the pupils must be at least 50-60 pixels at 720p.
- Lighting not less than 150 lux with face evenly illuminated.
| Example of proper camera position |
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| Example of bad camera position |
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However, if your video image does not meet these guidelines, you can check to see if recognition will work. If the face recognition quality turns out to be unsatisfactory, we may consider the module modification to suit your conditions. Please contact our technical support team by following these instructions. Technical support team member will request the necessary information (for example, access to the stream you use for recognition) and will let you know if the improvements are possible and when we will implement them.
Detection zone¶
By default, the recognition system searches for faces over all the camera field of view. You can select specific polygonal area(s) to detect faces in by clicking Set up the detection zone. This settings may help you to reduce false detections. Areas are set individually for each camera, even if you select a non-configurable preset.
Lists of persons¶
Flussonic Watcher supports face recognition in 1:N identification mode, that is, it allows you to find out which person corresponds to the face detected in the frame. When you enable face recognition on the camera, Flussonic Watcher starts detecting faces, and if there are lists of faces, also recognize the detected faces.
For face recognition to work, you should populate the person database in Watcher by creating persons and lists of persons. A person is a sample face saved in the Watcher database with accompanying attributes, such as ID, name, etc. A list of persons is a set of persons united on some logical basis, for example, people from the same department or having the same access level to the premises.
You can create one or several person list(s) and add several persons to them. As the persons pass under the camera, events about their passages will appear in the system on the Events tab. If a face is recognized, then the person’s name will be indicated in the event, and if the face is detected but not recognized, then you will see an identifier of a newly created unknown person. You can edit such persons later or create new persons.
Each camera can recognize persons from one person list only. Both recognized and unrecognized persons are included in the lists linked to the corresponding cameras. If a face is detected or recognized on a camera that is not linked to any list, then the person is included in the Persons not on any list list.
Required permissions¶
The following user permissions are required to manage persons and person lists:
- Watcher Administrator can view, edit, or delete all persons and person lists in the system; OR
- Organization Administrator (owner) can view, create, edit, or delete only the persons and person lists within the owned Organization (first of them if many).
Integration with third party systems¶
With API, you can use the face recognition events in other systems (for example, when integrating with access control systems, when you want to allow only employees of a particular office to enter the door).
Use the External ID for integration with Access Control System or other third party system. At such integrations, Watcher usually have to transmit message about the person it has recognized. However, person databases in Watcher and external system are not related whatsoever. This is why you should enter the external ID of each person i.e. the ID person has in the external database. This will help the external system to understand which person the message from Watcher is related to and proceed with granting/denying access according to its internal logic or performing other actions.