python+opencv获取最小外接矩形

环境

python版本：3.8
opencv版本：4.3.0.36

代码

from PIL import Image
from pylab import *
import cv2
import numpy as np

# 读取图像到数组中
im = array(Image.open('./001.bmp'))

# 定义边界点
xs = [190.5,167.5,144.5,128.5,114.5,100.5,97.5,82.5,71.5,62.5,45.5,33.5,23.5,10.5,9.5,9.5,18.5,20.5,14.5,17.5,16.5,25.5,26.5,37.5,50.5,61.5,75.5,80.5,82.5,83.5,107.5,131.5,137.5,176.5,193.5,200.5,203.5,217.5,239.5,254.5,270.5,288.5,304.5,327.5,341.5,363.5,377.5,388.5,397.5,402.5,388.5,381.5,374.5,375.5,367.5,363.5,358.5,363.5,353.5,340.5,339.5,335.5,326.5,311.5,279.5,239.5,211.5,190.5]
ys = [374.13,366.13,363.13,361.13,365.13,361.13,357.13,362.13,373.13,376.13,369.13,365.13,354.13,342.13,329.13,317.13,311.13,296.13,283.13,272.13,258.13,247.13,216.13,184.13,158.13,129.13,98.13,82.13,52.13,42.13,34.13,31.13,15.13,10.12,13.13,26.13,31.13,22.13,22.13,28.13,41.13,54.13,65.13,81.13,92.13,97.13,112.13,148.13,176.13,192.13,204.13,213.13,223.13,245.13,255.13,269.13,281.13,296.13,302.13,313.13,325.13,338.13,358.13,381.13,391.13,390.13,380.13,374.13]

plt.plot(xs, ys, 'r*') # 绘制边界点

# 获取最小外接矩形
contour = np.vstack((xs, ys)) #将x，y竖着拼接
contour = np.array(contour.T, dtype=np.float32)
rect = cv2.minAreaRect(contour) # 得到最小外接矩形的（中心(x,y), (宽,高), 旋转角度）
box = cv2.boxPoints(rect) # cv2.boxPoints(rect) for OpenCV 3.x 获取最小外接矩形的4个顶点坐标
box = np.int0(box)

# 绘制最小外接矩形
plt.plot(box[1], box[0], color='g')
plt.plot(box[2], box[1], color='g')
plt.plot(box[3], box[2], color='g')
plt.plot(box[0], box[3], color='g')

# 添加标题，显示绘制的图像

title("pic1.png")
imshow(im)
plt.show()

效果