Dice Coefficient Calculator
Calculate the Dice coefficient to evaluate overlap in image segmentation tasks.
Inputs
Dice Coefficient
0.7619
Step by step
Dice = 2×Intersection / (|Pred| + |GT|)
2×800 / (1000 + 1100)
= 0.761905
How it works
The Dice coefficient (F1 for sets) measures overlap between predicted and ground truth segmentation masks: Dice = 2×|Intersection| / (|Prediction| + |Ground Truth|). It ranges from 0 (no overlap) to 1 (perfect overlap) and is the standard metric for medical image segmentation tasks.
Formula
Dice Coefficient
Dice = 2 * |X ∩ Y| / (|X| + |Y|)
- |X ∩ Y|
- Number of pixels in both prediction and ground truth
Frequently Asked Questions
How does Dice relate to IoU?
Dice = 2*IoU / (1 + IoU). Dice is always ≥ IoU for the same prediction. Both measure overlap, but Dice gives more credit for partial overlap and is preferred in medical imaging where class imbalance is severe.
Why is Dice preferred over accuracy for segmentation?
In segmentation, the background class often dominates (>95% of pixels), making pixel accuracy misleading. Dice focuses exclusively on the overlap of the foreground class of interest.