Calculating an intersection over a union between two images

To understand how accurate the proposed regions are, we use a metric named Intersection over Union (IoU). IoU can be visualized as follows:

Note that, in the preceding picture, the blue box (lower one) is the ground truth and the red box (the upper rectangle) is the region proposal.

The intersection over the union of the region proposal is calculated as the ratio of the intersection of the proposal and the ground truth over the union of the region proposal and the ground truth.

How to do it...

IoU is calculated as follows (the code file is available as Selective_search.ipynb in GitHub):

1. Define the IoU extraction function, demonstrated in the following code:

from...