getTextDetection method

Future<GetTextDetectionResponse> getTextDetection({ required String jobId, int? maxResults, String? nextToken, })

Gets the text detection results of a Amazon Rekognition Video analysis started by StartTextDetection.

Text detection with Amazon Rekognition Video is an asynchronous operation. You start text detection by calling StartTextDetection which returns a job identifier (JobId) When the text detection operation finishes, Amazon Rekognition publishes a completion status to the Amazon Simple Notification Service topic registered in the initial call to StartTextDetection. To get the results of the text detection operation, first check that the status value published to the Amazon SNS topic is SUCCEEDED. if so, call GetTextDetection and pass the job identifier (JobId) from the initial call of StartLabelDetection.

GetTextDetection returns an array of detected text (TextDetections) sorted by the time the text was detected, up to 50 words per frame of video.

Each element of the array includes the detected text, the precentage confidence in the acuracy of the detected text, the time the text was detected, bounding box information for where the text was located, and unique identifiers for words and their lines.

Use MaxResults parameter to limit the number of text detections returned. If there are more results than specified in MaxResults, the value of NextToken in the operation response contains a pagination token for getting the next set of results. To get the next page of results, call GetTextDetection and populate the NextToken request parameter with the token value returned from the previous call to GetTextDetection.

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

Parameter jobId : Job identifier for the text detection operation for which you want results returned. You get the job identifer from an initial call to StartTextDetection.

Parameter maxResults : Maximum number of results to return per paginated call. The largest value you can specify is 1000.

Parameter nextToken : If the previous response was incomplete (because there are more labels to retrieve), Amazon Rekognition Video returns a pagination token in the response. You can use this pagination token to retrieve the next set of text.

Implementation

Future<GetTextDetectionResponse> getTextDetection({
  required String jobId,
  int? maxResults,
  String? nextToken,
}) async {
  ArgumentError.checkNotNull(jobId, 'jobId');
  _s.validateStringLength(
    'jobId',
    jobId,
    1,
    64,
    isRequired: true,
  );
  _s.validateNumRange(
    'maxResults',
    maxResults,
    1,
    1152921504606846976,
  );
  _s.validateStringLength(
    'nextToken',
    nextToken,
    0,
    255,
  );
  final headers = <String, String>{
    'Content-Type': 'application/x-amz-json-1.1',
    'X-Amz-Target': 'RekognitionService.GetTextDetection'
  };
  final jsonResponse = await _protocol.send(
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    // TODO queryParams
    headers: headers,
    payload: {
      'JobId': jobId,
      if (maxResults != null) 'MaxResults': maxResults,
      if (nextToken != null) 'NextToken': nextToken,
    },
  );

  return GetTextDetectionResponse.fromJson(jsonResponse.body);
}