tf.metrics.mean_iou( labels, predictions, num_classes, weights=None, metrics_collections=None, updates_collections=None, name=None )
Defined in tensorflow/python/ops/metrics_impl.py
.
Calculate per-step mean Intersection-Over-Union (mIOU).
Mean Intersection-Over-Union is a common evaluation metric for semantic image segmentation, which first computes the IOU for each semantic class and then computes the average over classes. IOU is defined as follows: IOU = true_positive / (true_positive + false_positive + false_negative). The predictions are accumulated in a confusion matrix, weighted by weights
, and mIOU is then calculated from it.
For estimation of the metric over a stream of data, the function creates an update_op
operation that updates these variables and returns the mean_iou
.
If weights
is None
, weights default to 1. Use weights of 0 to mask values.
labels
: A Tensor
of ground truth labels with shape [batch size] and of type int32
or int64
. The tensor will be flattened if its rank > 1.predictions
: A Tensor
of prediction results for semantic labels, whose shape is [batch size] and type int32
or int64
. The tensor will be flattened if its rank > 1.num_classes
: The possible number of labels the prediction task can have. This value must be provided, since a confusion matrix of dimension = [num_classes, num_classes] will be allocated.weights
: Optional Tensor
whose rank is either 0, or the same rank as labels
, and must be broadcastable to labels
(i.e., all dimensions must be either 1
, or the same as the corresponding labels
dimension).metrics_collections
: An optional list of collections that mean_iou
should be added to.updates_collections
: An optional list of collections update_op
should be added to.name
: An optional variable_scope name.mean_iou
: A Tensor
representing the mean intersection-over-union.update_op
: An operation that increments the confusion matrix.ValueError
: If predictions
and labels
have mismatched shapes, or if weights
is not None
and its shape doesn't match predictions
, or if either metrics_collections
or updates_collections
are not a list or tuple.RuntimeError
: If eager execution is enabled.
© 2018 The TensorFlow Authors. All rights reserved.
Licensed under the Creative Commons Attribution License 3.0.
Code samples licensed under the Apache 2.0 License.
https://www.tensorflow.org/api_docs/python/tf/metrics/mean_iou