rect(top, left, bottom, right)からIoU計算する

IoUとは: Intersection over Union (IoU) for object detection - PyImageSearch

import numpy as np
from sklearn.metrics import jaccard_score

N = 100 # 精度
# rect:  top, left, bottom, right (0~1, float)
def rect_to_array(rect):
    top, left, bottom, right = (np.array(rect) * N).astype(int)
    box = np.pad(np.ones((bottom - top, right - left)), ((top, N - bottom), (left, N - right)))
    return box

def iou(true, pred):
    true_array = rect_to_array(true)
    pred_array = rect_to_array(pred)
    return jaccard_score(true_array.flatten(), pred_array.flatten())

print (iou((0.5,0.5,1,1), (0,0, 0.8, 0.8)))
# 0.1125