Calculating percentage of Bounding box overlap, for image detector evaluation

Question

In testing an object detection algorithm in large images, we check our detected bounding boxes against the coordinates given for the ground truth rectangles.

Accordi

Answer 1

A Simple way

(Image is not drawn to scale)

from shapely.geometry import Polygon


def calculate_iou(box_1, box_2):
    poly_1 = Polygon(box_1)
    poly_2 = Polygon(box_2)
    iou = poly_1.intersection(poly_2).area / poly_1.union(poly_2).area
    return iou


box_1 = [[511, 41], [577, 41], [577, 76], [511, 76]]
box_2 = [[544, 59], [610, 59], [610, 94], [544, 94]]

print(calculate_iou(box_1, box_2))

The result will be 0.138211... which means 13.82%.