图像主体裁剪

import cv2
import numpy as np
image=cv2.imread('C:/Users/xpp/Desktop/Lena.png')
img=cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)
ret,thresh=cv2.threshold(img,230,255,cv2.THRESH_BINARY_INV)
contours,hierarchy=cv2.findContours(thresh,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_SIMPLE)
dot=[]
for c in contours:
    #检测边界坐标
    min_list=[]#保存单个轮廓的信息，x，y，w，h，area，x，y为起始点坐标
    x,y,w,h=cv2.boundingRect(c)#计算点集最外面的矩形边界
    min_list.append(x)
    min_list.append(y)
    min_list.append(w)
    min_list.append(h)
    min_list.append(w*h)
    dot.append(min_list)
#检测最大矩形的x，y，w，h，area
max_area=dot[0][4]#把第一个矩形面积当作最大矩形面积
for inlist in dot:
    area=inlist[4]
    if area>=max_area:
        x=inlist[0]
        y=inlist[1]
        w=inlist[2]
        h=inlist[3]
        max_area=area
#在原图上画出最大的矩形
cv2.rectangle(image,(x,y),(x+w,y+h ),(0,255,0),1)
cv2.namedWindow('img',cv2.WINDOW_NORMAL)
cv2.resizeWindow('img',460,460)
cv2.imshow('img',image)
cv2.imwrite('C:/Users/xpp/Desktop/resut.png',image)
result=Image.open('C:/Users/xpp/Desktop/image.png')
region=result.crop((x,y,x+w,y+h))
region.save('C:/Users/xpp/Desktop/result.png')
cv2.waitKey(0)