IOU v.s. GIOU

[abbr]

IOU stands for Intersection Over Union.

GIOU stands for Generalized IOU.

[formula]

IOU = area of intersection / area of union

GIOU= IOU — ( |C(area of union)| / |C| )

where

C is the universal of A and B.

(What is union and intersection and C? see the following handmade figure.)

(In this figure, C=U.)

More details on the formula, see the following figure.

IOU has two disadvantages:

(1) IOU can not represent the effect of object detection.

(2) See the following figure.

[ref]

Generalized Intersection over Union (stanford.edu)

[CVPR2019]：Generalized Intersection over Union — 知乎 (zhihu.com)