detectCustomLabels method
Detects custom labels in a supplied image by using an Amazon Rekognition Custom Labels model.
You specify which version of a model version to use by using the
ProjectVersionArn
input parameter.
You pass the input image as base64-encoded image bytes or as a reference to an image in an Amazon S3 bucket. If you use the AWS CLI to call Amazon Rekognition operations, passing image bytes is not supported. The image must be either a PNG or JPEG formatted file.
For each object that the model version detects on an image, the API
returns a (CustomLabel
) object in an array
(CustomLabels
). Each CustomLabel
object provides
the label name (Name
), the level of confidence that the image
contains the object (Confidence
), and object location
information, if it exists, for the label on the image
(Geometry
).
During training model calculates a threshold value that determines if a
prediction for a label is true. By default,
DetectCustomLabels
doesn't return labels whose confidence
value is below the model's calculated threshold value. To filter labels
that are returned, specify a value for MinConfidence
that is
higher than the model's calculated threshold. You can get the model's
calculated threshold from the model's training results shown in the Amazon
Rekognition Custom Labels console. To get all labels, regardless of
confidence, specify a MinConfidence
value of 0.
You can also add the MaxResults
parameter to limit the number
of labels returned.
This is a stateless API operation. That is, the operation does not persist any data.
This operation requires permissions to perform the
rekognition:DetectCustomLabels
action.
May throw ResourceNotFoundException. May throw ResourceNotReadyException. May throw InvalidS3ObjectException. May throw InvalidParameterException. May throw ImageTooLargeException. May throw LimitExceededException. May throw AccessDeniedException. May throw InternalServerError. May throw ThrottlingException. May throw ProvisionedThroughputExceededException. May throw InvalidImageFormatException.
Parameter projectVersionArn
:
The ARN of the model version that you want to use.
Parameter maxResults
:
Maximum number of results you want the service to return in the response.
The service returns the specified number of highest confidence labels
ranked from highest confidence to lowest.
Parameter minConfidence
:
Specifies the minimum confidence level for the labels to return. Amazon
Rekognition doesn't return any labels with a confidence lower than this
specified value. If you specify a value of 0, all labels are return,
regardless of the default thresholds that the model version applies.
Implementation
Future<DetectCustomLabelsResponse> detectCustomLabels({
required Image image,
required String projectVersionArn,
int? maxResults,
double? minConfidence,
}) async {
ArgumentError.checkNotNull(image, 'image');
ArgumentError.checkNotNull(projectVersionArn, 'projectVersionArn');
_s.validateStringLength(
'projectVersionArn',
projectVersionArn,
20,
2048,
isRequired: true,
);
_s.validateNumRange(
'maxResults',
maxResults,
0,
1152921504606846976,
);
_s.validateNumRange(
'minConfidence',
minConfidence,
0,
100,
);
final headers = <String, String>{
'Content-Type': 'application/x-amz-json-1.1',
'X-Amz-Target': 'RekognitionService.DetectCustomLabels'
};
final jsonResponse = await _protocol.send(
method: 'POST',
requestUri: '/',
exceptionFnMap: _exceptionFns,
// TODO queryParams
headers: headers,
payload: {
'Image': image,
'ProjectVersionArn': projectVersionArn,
if (maxResults != null) 'MaxResults': maxResults,
if (minConfidence != null) 'MinConfidence': minConfidence,
},
);
return DetectCustomLabelsResponse.fromJson(jsonResponse.body);
}