def __init__(self, matching_iou_threshold=0.5, metric_prefix=None):
    """Constructor.

    Args:
      matching_iou_threshold: IOU threshold to use for matching groundtruth
        boxes to detection boxes.
      metric_prefix: (optional) string prefix for metric name; if None, no
        prefix is used.

    """
    super(VRDDetectionEvaluator, self).__init__([])
    self._matching_iou_threshold = matching_iou_threshold
    self._evaluation = _VRDDetectionEvaluation(
        matching_iou_threshold=self._matching_iou_threshold)
    self._image_ids = set([])
    self._metric_prefix = (metric_prefix + '_') if metric_prefix else ''
    self._evaluatable_labels = {}
    self._negative_labels = {}
Constructor.

    Args:
      matching_iou_threshold: IOU threshold to use for matching groundtruth
        boxes to detection boxes.
      metric_prefix: (optional) string prefix for metric name; if None, no
        prefix is used.

    
inference_api/src/main/object_detection/utils/vrd_evaluation.py