Face Detection

This Project aims to detect faces in images.

Data models

This project uses the Face data model.

Configuration

This project uses a configuration YAML with the following fields:

• face_detector: Specifies the name and parameters of the face detection model. It must have the following fields:

  • model_name: Name of the model.

  • params: The parameters of the models’ python class.

• context_broker:

  • host: IP address of the Context Broker.

  • port: Port of the Context Broker.

  • notification_uri: URI where the subscription notifications will be sent.

  • check_subscription_conflicts: Flag if the subscription conflicts should be checked before creating them.

• api:

  • host: Bind IP address of the API server.

  • port: Bind port of the API server.

  • allowed_origins: List of origins that should be permitted to make cross-origin requests.

  • local_image_storage: Flags if the images are stored locally and can be accessed by their path or must be retrieved from a URL.

• subscriptions: List of subscriptions to create on the context broker. Each element can have the following fields:

  • entity_type: Entity type to subscribe to.

  • watched_attributes: List of attributes to subscribe to.

  • query: Query to filter the entities to subscribe to.

Example:

face_detector:
  model_name: face_detector_retinaface
  params:
    weights_path: ../../../data/models/face_detector_retinaface/Resnet50_Final.pth
    model_name: resnet50
    confidence_threshold: 0.7
    landmarks: False
    nms_threshold: 0.4
    use_cuda: False

context_broker:
  host: 192.168.0.100
  port: 1026
  notification_uri: http://192.168.0.100:8080/ngsi-ld/v1/notify
  check_subscription_conflicts: True

api:
  host: 0.0.0.0
  port: 8080
  allowed_origins: []
  local_image_storage: True

subscriptions:
  - entity_type: Image
    watched_attributes: ["purpose"]
    query: "purpose==%22FaceDetection%22"

API

The API allows the Project to be executed as a service. It has automatic and interactive documentation generated with swagger-ui on /docs and redoc on /redoc.

It can be executed with api.py. The --help option can be used to get a list of accepted arguments:

python api.py --help

usage: api.py [-h] [--config CONFIG] [--log-level {DEBUG,INFO,WARN,ERROR,CRITICAL}]

optional arguments:
  -h, --help            show this help message and exit
  --config CONFIG       Path to the configuration yaml (default: 'config.yaml')
  --log-level {DEBUG,INFO,WARN,ERROR,CRITICAL}
                        Log level (default: INFO)

Endpoints

• GET /

  Returns the name and version of the API.

  • Response

    application/json

    {
      "title": "Face Detection API",
      "version": "0.2.0"
    }
    

• POST /predict

  Predict bounding boxes of the faces in an image. It returns a list of data models for each detected face. The response type can be specified with the accept header (application/json or application/ld+json).

  • Request body

    A JSON with the following fields:

    • entity_id: The id of an image entity in the context broker to perform face detection on.

    • post_to_broker: Flag if the generated data models should be posted to the context broker. Defaults to true.

    
    
    application/json

    {
      "entity_id": "string",
      "post_to_broker": true
    }
    

  • Response

    A list with the generated data models (one for each face) with the following fields:

    • id: The id of the entity on the context broker.

    • dateObserved: The date when the data model was generated.

    • type: The type of the data model (Face).

    • image: The id of the source image entity.

    • boundingBox: The bounding box of the face in the image with relative image coordinates.

    • detectionConfidence: The confidence of the detection.

    
    
    application/json

    [
      {
        "id": "urn:ngsi-ld:Face:H86LoussEe28ohtRGIBEXw",
        "dateObserved": "2023-05-05T10:03:46.306881",
        "type": "Face",
        "image": "urn:ngsi-ld:Image:bw97--NbzigD_jXd979yUpZCBTMOXZ0pdlnUKC5L-pw",
        "boundingBox": {
          "xmin": 0.66875,
          "ymin": 0.21481481481481482,
          "xmax": 0.7505208333333333,
          "ymax": 0.40185185185185185
        },
        "detectionConfidence": 0.9998043179512024,
        "age": null,
        "gender": null,
        "genderConfidence": null,
        "emotion": null,
        "emotionConfidence": null,
        "features": null,
        "featuresAlgorithm": null,
        "recognitionDomain": null,
        "recognized": false,
        "recognizedDistance": null,
        "recognizedPerson": null
      }
    ]
    

    application/ld+json

    [
      {
        "id": "urn:ngsi-ld:Face:qWLNOussEe2U6BtRGIBEXw",
        "type": "Face",
        "@context": [
          "https://uri.etsi.org/ngsi-ld/v1/ngsi-ld-core-context.jsonld"
        ],
        "dateObserved": {
          "type": "Property",
          "value": {
            "@type": "DateTime",
            "@value": "2023-05-05T10:07:37Z"
          }
        },
        "image": {
          "type": "Relationship",
          "object": "urn:ngsi-ld:Image:bw97--NbzigD_jXd979yUpZCBTMOXZ0pdlnUKC5L-pw"
        },
        "boundingBox": {
          "type": "Property",
          "value": {
            "xmin": 0.66875,
            "ymin": 0.21481481481481482,
            "xmax": 0.7505208333333333,
            "ymax": 0.40185185185185185
          }
        },
        "detectionConfidence": {
          "type": "Property",
          "value": 0.9998043179512024
        },
        "recognized": {
          "type": "Property",
          "value": false
        },
        "dateModified": {
          "type": "Property",
          "value": {
            "@type": "DateTime",
            "@value": "2023-05-05T10:07:37Z"
          }
        },
        "dateCreated": {
          "type": "Property",
          "value": {
            "@type": "DateTime",
            "@value": "2023-05-05T10:07:37Z"
          }
        }
      }
    ]
    

• POST /ngsi-ld/v1/notify

  Route to notify the activation of a subscription from a context broker.

  • Query parameters

    subscriptionId: The id of the subscription.

  • Request body

    A JSON with the following fields:

    • id: The id of the notification.

    • type: Notification.

    • subscriptionId: The id of the subscription.

    • notifiedAt: The date when the notification was sent.

    • data: A list with the entities notified.

    
    
    application/json

    {
      "id": "string",
      "type": "Notification",
      "subscriptionId": "string",
      "notifiedAt": "string",
      "data": []
    }
    

  • Response

    204 no content: If the notification was processed successfully.