Video face detection: findface-video-manager and findface-video-worker

Note

The findface-video-worker is delivered in a CPU-accelerated (findface-video-worker) and a GPU-accelerated (findface-video-worker-gpu) packages.

In this section:

Functions of findface-video-manager

The findface-video-manager service is the part of the video face detection module that is used for managing the video face detection functionality.

The findface-video-manager service interfaces with findface-video-worker as follows:

  • It supplies findface-video-worker with settings and the list of to-be-processed video streams. To do so, it issues a so-called job, a video processing task that contains configuration settings and stream data.
  • In a distributed system, it distributes video streams (jobs) across vacant findface-video-worker instances.

Note

Configuration settings passed via jobs have priority over the findface-video-manager configuration file.

The findface-video-mananger service functioning requires ETCD, third-party software that implements a distributed key-value store for findface-video-manager. In the FindFace core, ETCD is used as a coordination service, providing the video face detector with fault tolerance.

Functionality:

  • allows for configuring video face detection parameters,
  • allows for managing the list of to-be-processed video streams,
  • implements video face detection management.

Functions of findface-video-worker

The findface-video-worker (or findface-video-worker-gpu) service is the part of the video face detection module, which recognizes faces in video. It can work with both live streams and files, and supports most video formats and codecs that can be decoded by FFmpeg.

The findface-video-worker service interfaces with the findface-video-manager and findface-facerouter services as follows:

  • By request, findface-video-worker gets a job with settings and the list of to-be-processed video streams from findface-video-manager.
  • The findface-video-worker posts extracted normalized face images, along with the full frames and meta data (such as bbox, camera ID and detection time) to the findface-facerouter service for further processing.

Note

In FindFace Security, the findface-facerouter functions are performs by findface-security.

Functionality:

  • detects faces in video,
  • extracts normalized face images,
  • searches for the best face snapshot,
  • snapshot deduplication (only one snapshot per face detection event).

When processing video, findface-video-worker consequently uses the following algorithms:

  • Motion detection. Used to reduce resource consumption. Only when the motion detector recognizes motion of certain intensity that the face tracker can be triggered.
  • Face tracking. The face tracker tracks, detects and captures faces in video. It can simultaneously be working with several faces. It also searches for the best face snapshot, using an embedded neural network. After the best face snapshot is found, it is posted to findface-facerouter.

The best face snapshot can be found in one of the following modes:

  • Real-time
  • Offline

Real-Time Mode

In the real-time mode, findface-video-worker posts a face immediately after it appears in the camera field of view.

  • If rt-perm=True, the face tracker searches for the best face snapshot within each time period equal to rt-delay and posts it to findface-facerouter.
  • If rt-perm=False, the face tracker searches for the best face snapshot dynamically:
    1. First, the face tracker estimates whether the quality of a face snapshot exceeds a pre-defined threshold value. If so, the snapshot is posted to findface-facerouter.
    2. The threshold value increases after each post. Each time the face tracker gets a higher quality snapshot of the same face, it is posted.
    3. When the face disappears from the camera field of view, the threshold value resets to default.

By default, the real-time mode is disabled (realtime=false in the /etc/findface-video-manager.conf file).

Offline Mode

The offline mode is less storage intensive than the real-time one as in this mode findface-video-worker posts only one snapshot per track, but of the highest quality. In this mode, the face tracker buffers a video stream with a face in it until the face disappears from the camera field of view. Then the face tracker picks up the best face snapshot from the buffered video and posts it to findface-facerouter.

By default, the offline mode is enabled (overall=true in the /etc/findface-video-manager.conf file).

Configure Video Face Detection

The video face detector configuration is done through the following configuration files:

  1. The findface-video-manager configuration file /etc/findface-video-manager.conf:

    etcd:
  dial_timeout: 3s
  endpoints: 127.0.0.1:2379
exp_backoff:
  enabled: false
  factor: 2
  flush_interval: 2m0s
  max_delay: 1m0s
  min_delay: 1s
job_scheduler_script: ''
kafka:
  enabled: false
  endpoints: 127.0.0.1:9092
listen: 127.0.0.1:18810
master:
  lease_ttl: 10
  self_url: 127.0.0.1:18811
  self_url_http: 127.0.0.1:18811
ntls:
  enabled: false
  update_interval: 1m0s
  url: http://127.0.0.1:3185/
prometheus:
  jobs_processed_duration_buckets:
  - 1
  - 30
  - 60
  - 500
  - 1800
  - 3600
  - 21600
  - .inf
router_url: http://127.0.0.1:18820/v0/frame
rpc:
 heart_beat_timeout: 4s
 listen: 127.0.0.1:18811
stream_settings:
  additional_body: []
  additional_headers: []
  api_ssl_verify: true
  api_timeout: 15000
  det_period: 8
  disable_drops: false
  draw_track: false
  fd_frame_height: -1
  ffmpeg_format: ''
  ffmpeg_params: []
  image_arg: photo
  jpeg_quality: 95
  max_candidates: 0
  max_face_size: 0
  md_scale: 0.3
  md_threshold: 0.002
  min_d_score: -1000
  min_face_size: 0
  min_score: -2
  npersons: 4
  only_norm: false
  overall: true
  parse_sei: false
  post_uniq: true
  realtime: false
  realtime_dly: 500
  realtime_post_perm: false
  roi: ''
  rot: ''
  send_track: 0
  tracker_threads: 4
  uc_max_avg_shift: 10
  uc_max_dup: 3
  uc_max_time_diff: 30
stream_settings_gpu:
  ffmpeg_format: ''
  ffmpeg_params: []
  filter_max_face_size: 8192
  filter_min_face_size: 1
  filter_min_quality: -2
  imotion_threshold: 0
  jpeg_quality: 95
  normalized_only: false
  overall_only: false
  play_speed: -1
  realtime_post_every_interval: false
  realtime_post_interval: 1
  roi: ''
  rot: ''
  router_body: []
  router_headers: []
  router_timeout_ms: 15000
  router_verify_ssl: true
  start_stream_timestamp: 0
  use_stream_timestamp: false

    When configuring findface-video-manager, refer to the following parameters:

    Option Description
    router_url IP address and port of the findface-facerouter host to receive detected faces from findface-video-worker. In FindFace Security, findface-facerouter functions are performed by findface-security. Default value: http://127.0.0.1:18820/v0/frame.
    etcd -> endpoints IP address and port of the etcd service. Default value: 127.0.0.1:2379.
    ntls -> enabled If true, findface-video-manager will send a job to findface-video-worker only if the total number of processed cameras does not exceed the allowed number of cameras from the license. Default value: false.
    ntls -> url IP address and port of the findface-ntls host. Default value: http://127.0.0.1:3185/.

  2. If you opt for the CPU-accelerated package findface-video-worker, use the /etc/findface-video-worker.ini configuration file:

    ntls-addr=127.0.0.1:3133
mgr-static=127.0.0.1:18811
capacity=10
#mgr-exec=shell command with arguments

    If you opt for the GPU-accelerated package findface-video-worker-gpu, use the /etc/findface-video-worker-gpu.ini configuration file.

    ## cuda device number
device_number = 0

## read streams from file, do not use VideoManager
input =

## exit on first finished job, only when --input specified
exit_on_first_finished = false

## models directory
models_dir = /usr/share/findface-gpudetector/models

## batch size
batch_size = 1

## http server port for metrics, 0=do not start server
metrics_port = 0

## resize scale, 1=do not resize
resize_scale = 1.0

## maximum number of streams
capacity = 30

## command to obtain videomanager's grpc ip:port
mgr_cmd =

## videomanager grpc ip:port
mgr_static = 127.0.0.1:18811

## ntls server ip:port
ntls_addr = 127.0.0.1:3133

## debug: save faces to dir
save_dir =

## minimum face size
min_face_size = 60

## preinit detector for specified resolutions: "640x480;1920x1080"
resolutions =

# worker labels: "k=v;group=enter"
labels =

## use timestamps from SEI packet
use_time_from_sei = false

#------------------------------
[streamer]
#------------------------------
## streamer server port, 0=disabled
port = 9999

## streamer url - how to access this worker on streamer_port
url = ws://127.0.0.1:9999/stream/

#------------------------------
[liveness]
#------------------------------
## path to liveness fnk
fnk =

## liveness threshold
threshold = 0.945

## liveness internal algo param
interval = 1.0

## liveness internal algo param
stdev_cnt = 1

#------------------------------
[video_decoder]
#------------------------------
## decode video on cpu
cpu = false

#------------------------------
[send]
#------------------------------
## posting faces threads
threads = 8

## posting faces maximum queue size
queue_limit = 256

#------------------------------
[tracker]
#------------------------------
## max face miss duration, sec
miss_interval = 1.0

## overlap threshold
overlap_threshold = 0.25```

    When configuring findface-video-worker/findface-video-worker-gpu, refer to the following parameters:

    Parameter Description
    ntls-addr IP address and port of the findface-ntls host.
    mgr-static IP address of the findface-video-manager host to provide findface-video-worker with settings and the list of to-be-processed streams.
    capacity Maximum number of video streams to be processed by findface-video-worker.
    mgr-exec (Optional, instead of the mgr-static parameter) A script to describe dynamic IP address of the findface-video-manager host.
    labels (Only for GPU, optional). Labels used to allocate a video face detector instance to a certain group of cameras. See Allocate findface-video-worker to Camera Group.
    fnk (Only for GPU, optional). Path to the face liveness detector.