mIoU#

ignite.metrics.mIoU(cm, ignore_index=None)[source]#

Calculates mean Intersection over Union using ConfusionMatrix metric.

Parameters

cm (ConfusionMatrix) – instance of confusion matrix metric
ignore_index (Optional[int]) – index to ignore, e.g. background index

Returns

MetricsLambda

Return type

MetricsLambda

Examples

cm = ConfusionMatrix(num_classes=3)
metric = mIoU(cm, ignore_index=0)
metric.attach(default_evaluator, 'miou')
y_true = torch.Tensor([0, 1, 0, 1, 2]).long()
y_pred = torch.Tensor([
    [0.0, 1.0, 0.0],
    [0.0, 1.0, 0.0],
    [1.0, 0.0, 0.0],
    [0.0, 1.0, 0.0],
    [0.0, 1.0, 0.0],
])
state = default_evaluator.run([[y_pred, y_true]])
print(state.metrics['miou'])

0.24999...