searchFaces method

Future<SearchFacesResponse> searchFaces({ required String collectionId, required String faceId, double? faceMatchThreshold, int? maxFaces, })

For a given input face ID, searches for matching faces in the collection the face belongs to. You get a face ID when you add a face to the collection using the IndexFaces operation. The operation compares the features of the input face with faces in the specified collection. The operation response returns an array of faces that match, ordered by similarity score with the highest similarity first. More specifically, it is an array of metadata for each face match that is found. Along with the metadata, the response also includes a confidence value for each face match, indicating the confidence that the specific face matches the input face.

For an example, see Searching for a Face Using Its Face ID in the Amazon Rekognition Developer Guide.

This operation requires permissions to perform the rekognition:SearchFaces action.

May throw InvalidParameterException. May throw AccessDeniedException. May throw InternalServerError. May throw ThrottlingException. May throw ProvisionedThroughputExceededException. May throw ResourceNotFoundException.

Parameter collectionId : ID of the collection the face belongs to.

Parameter faceId : ID of a face to find matches for in the collection.

Parameter faceMatchThreshold : Optional value specifying the minimum confidence in the face match to return. For example, don't return any matches where confidence in matches is less than 70%. The default value is 80%.

Parameter maxFaces : Maximum number of faces to return. The operation returns the maximum number of faces with the highest confidence in the match.

Implementation

Future<SearchFacesResponse> searchFaces({
  required String collectionId,
  required String faceId,
  double? faceMatchThreshold,
  int? maxFaces,
}) async {
  ArgumentError.checkNotNull(collectionId, 'collectionId');
  _s.validateStringLength(
    'collectionId',
    collectionId,
    1,
    255,
    isRequired: true,
  );
  ArgumentError.checkNotNull(faceId, 'faceId');
  _s.validateNumRange(
    'faceMatchThreshold',
    faceMatchThreshold,
    0,
    100,
  );
  _s.validateNumRange(
    'maxFaces',
    maxFaces,
    1,
    4096,
  );
  final headers = <String, String>{
    'Content-Type': 'application/x-amz-json-1.1',
    'X-Amz-Target': 'RekognitionService.SearchFaces'
  };
  final jsonResponse = await _protocol.send(
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    // TODO queryParams
    headers: headers,
    payload: {
      'CollectionId': collectionId,
      'FaceId': faceId,
      if (faceMatchThreshold != null)
        'FaceMatchThreshold': faceMatchThreshold,
      if (maxFaces != null) 'MaxFaces': maxFaces,
    },
  );

  return SearchFacesResponse.fromJson(jsonResponse.body);
}