import cv2  
import numpy as np
 
img = cv2.imread("data/test/test2.png")  
dst = 255- img
gray = cv2.cvtColor(dst,cv2.COLOR_BGR2GRAY)  
ret, binary = cv2.threshold(gray,127,255,cv2.THRESH_BINARY)  
 
contours, hierarchy = cv2.findContours(binary,cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE)

minx = 65523
miny = 65523
maxx = 0
maxy = 0

for contour in contours:
    boundRect = cv2.boundingRect(contour)
    (x,y,w,h)=boundRect
    if x<minx:
        minx=x
    if y<miny:
        miny=y
    if x+w>maxx:
        maxx=x+w
    if y+h>maxy:
        maxy=y+h
cutw=maxx-minx
cuth=maxy-miny
# w>h
if cutw>cuth:
    cuty1=int((maxy+miny)/2-cutw/2)
    cuty2=int((maxy+miny)/2+cutw/2)
    img = img[cuty1:cuty2,minx:maxx]
if cutw<cuth:
    cutx1=int((maxx+minx)/2-cuth/2)
    cutx2=int((maxx+minx)/2+cuth/2)
    img = img[miny:maxy,cutx1:cutx2] 
# img = img[miny:maxy,minx:maxx]
cv2.imwrite("cctmp.png", img)