# Jaccard Index / Intersection over Union

IoU is a measure of the overlap between two bounding boxes (usually between prediction and ground truth), used a lot in Object Detection.

Higher IoU indicates the predicted bounding box coordinates closely resembles the ground truth box coordinates.

$IoU=Area of UnionArea of Intersection $

The Jaccard index, also known as the Jaccard similarity coefficient, is a statistic used for gauging the similarity and diversity of sample sets. $J(A,B)=∣A∪B∣∣A∩B∣ $

However, they are identical in generally taking the ratio of **Intersection over Union**

### 3D IoU??

For Lidar Detection, they also need to measure IoU.

### Dice Coefficient

Found from here: https://www.kaggle.com/competitions/severstal-steel-defect-detection/overview/evaluation

$∣X∣+∣Y∣2∣X∩Y∣ $