mp.tasks.vision.FaceDetector

Class that performs face detection on images.

mp.tasks.vision.FaceDetector(
    lib: mp.tasks.vision.drawing_styles.face_landmarker.serial_dispatcher.SerialDispatcher,
    handle: ctypes.c_void_p,
    dispatcher: mp.tasks.vision.drawing_styles.face_landmarker.async_result_dispatcher.AsyncResultDispatcher,
    async_callback: _C_TYPES_RESULT_CALLBACK
)

lib The dispatch library to use for the face detector.
handle The C pointer to the face detector.
dispatcher The async result handler for the face detector.
async_callback The c callback for the face detector.

Methods

close

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close()

Shuts down the MediaPipe task instance.

create_from_model_path

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@classmethod
create_from_model_path(
    model_path: str
) -> 'FaceDetector'

Creates an FaceDetector object from a TensorFlow Lite model and the default FaceDetectorOptions.

Note that the created FaceDetector instance is in image mode, for detecting faces on single image inputs.

Args
model_path Path to the model.

Returns
FaceDetector object that's created from the model file and the default FaceDetectorOptions.

Raises
ValueError If failed to create FaceDetector object from the provided file such as invalid file path.
RuntimeError If other types of error occurred.

create_from_options

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@classmethod
create_from_options(
    options: mp.tasks.vision.FaceDetectorOptions
) -> 'FaceDetector'

Creates the FaceDetector object from face detector options.

Args
options Options for the face detector task.

Returns
FaceDetector object that's created from options.

Raises
ValueError If failed to create FaceDetector object from FaceDetectorOptions such as missing the model.
RuntimeError If other types of error occurred.

detect

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detect(
    image: mp.Image,
    image_processing_options: Optional[mp.tasks.vision.ImageProcessingOptions] = None
) -> mp.tasks.vision.FaceDetectorResult

Performs face detection on the provided MediaPipe Image.

Only use this method when the FaceDetector is created with the image running mode.

Args
image MediaPipe Image.
image_processing_options Options for image processing.

Returns
A face detection result object that contains a list of face detections, each detection has a bounding box that is expressed in the unrotated input frame of reference coordinates system, i.e. in [0,image_width) x [0, image_height), which are the dimensions of the underlying image data.

Raises
ValueError If any of the input arguments is invalid.
RuntimeError If face detection failed to run.

detect_async

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detect_async(
    image: mp.Image,
    timestamp_ms: int,
    image_processing_options: Optional[mp.tasks.vision.ImageProcessingOptions] = None
) -> None

Sends live image data (an Image with a unique timestamp) to perform face detection.

Only use this method when the FaceDetector is created with the live stream running mode. The input timestamps should be monotonically increasing for adjacent calls of this method. This method will return immediately after the input image is accepted. The results will be available via the result_callback provided in the FaceDetectorOptions. The detect_async method is designed to process live stream data such as camera input. To lower the overall latency, face detector may drop the input images if needed. In other words, it's not guaranteed to have output per input image.

The result_callback provides:

  • A face detection result object that contains a list of face detections, each detection has a bounding box that is expressed in the unrotated input frame of reference coordinates system, i.e. in [0,image_width) x [0,image_height), which are the dimensions of the underlying image data.
  • The input image that the face detector runs on.
  • The input timestamp in milliseconds.

Args
image MediaPipe Image.
timestamp_ms The timestamp of the input image in milliseconds.
image_processing_options Options for image processing.

Raises
ValueError If the current input timestamp is smaller than what the face detector has already processed.
RuntimeError If face detection failed to initialize.

detect_for_video

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detect_for_video(
    image: mp.Image,
    timestamp_ms: int,
    image_processing_options: Optional[mp.tasks.vision.ImageProcessingOptions] = None
) -> mp.tasks.vision.FaceDetectorResult

Performs face detection on the provided video frames.

Only use this method when the FaceDetector is created with the video running mode. It's required to provide the video frame's timestamp (in milliseconds) along with the video frame. The input timestamps should be monotonically increasing for adjacent calls of this method.

Args
image MediaPipe Image.
timestamp_ms The timestamp of the input video frame in milliseconds.
image_processing_options Options for image processing.

Returns
A face detection result object that contains a list of face detections, each detection has a bounding box that is expressed in the unrotated input frame of reference coordinates system, i.e. in [0,image_width) x [0, image_height), which are the dimensions of the underlying image data.

Raises
ValueError If any of the input arguments is invalid.
RuntimeError If face detection failed to run.

__enter__

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__enter__()

Returns self upon entering the runtime context.

__exit__

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__exit__(
    exc_type, exc_value, traceback
)

Shuts down the MediaPipe task instance on exit of the context manager.

Args
exc_type The exception type that caused the exit.
exc_value The exception value that caused the exit.
traceback The exception traceback that caused the exit.

Raises
RuntimeError If the MediaPipe FaceDetector task failed to close.