IOU Example

Let's walk through an example IOU calculation.

Steps

count true positives (TP)
count false positives (FP)
count false negatives (TN)
Intersection = TP
Union = TP + FP + FN
IOU = Intersection/Union

Mean IOU = [(3/7) + (2/6) + (3/4) + (1/6) ]/4 = 0.420