Segmentation

Dice coefficient

Definition

Overlap between predicted and ground-truth masks, weighting the intersection twice.

Formula

Range: [0, 1]

Inputs and outputs

• y_true: ground-truth mask (H×W or N×H×W)
• y_pred: predicted mask with the same shape

Returns: float or per-class array

Assumptions

No assumptions beyond valid, aligned inputs of the documented types.

Limitations

• Undefined when both masks are empty; the `empty` policy (1.0, NaN, or exclude) is always explicit.

Python API

import evalsuite as es

es.dice(y_true, y_pred)                    # macro over classes
es.dice(y_true, y_pred, aggregate="image")  # mean of per-image scores

References

1. Dice, L. R. (1945). Measures of the amount of ecologic association between species. Ecology, 26(3), 297–302.

Implementation status