exercises 笔记
IOU
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| def calculate_iou(box1, box2):
# 计算交集区域的坐标
x_left = max(box1[0], box2[0])
y_top = max(box1[1], box2[1])
x_right = min(box1[2], box2[2])
y_bottom = min(box1[3], box2[3])
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box是一个矩形，其四个参数两两一组，(box[0],box[1])是矩形左上角的坐标，(box[2],box[3])是矩形右下角的坐标，
用max,min函数得到
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| # 计算交集区域的面积
intersection_width = max(0, x_right - x_left)
intersection_height = max(0, y_bottom - y_top)
intersection_area = intersection_width * intersection_height
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wight与height为负时box1和box2无交集，用max将其置为0，这样得到的交集面积也为0
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| # 计算两个框各自的面积
area1 = (box1[2] - box1[0]) * (box1[3] - box1[1])
area2 = (box2[2] - box2[0]) * (box2[3] - box2[1])
# 计算并集面积
union_area = area1 + area2 - intersection_area
# 处理并集面积为0的情况（避免除以0）
if union_area == 0:
return 0.0
# 计算IoU
iou = intersection_area / union_area
return iou
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