cv2.findContours() 和 cv2.drawContours() 不显示预期结果

如何解决cv2.findContours() 和 cv2.drawContours() 不显示预期结果

我试图找出下图中每个形状的轮廓：1

我尝试了以下代码：

!pip install opencv-python
import cv2 as cv
import numpy as np
import matplotlib.pyplot as plt

from google.colab import drive
from google.colab.patches import cv2_imshow
drive.mount('/content/drive')

path='/content/drive/My Drive/NewApproach.png'
img= cv.imread(path,cv.IMREAD_UNCHANGED)

gray=cv.cvtColor(img,cv.COLOR_BGR2GRAY)
blur=cv.GaussianBlur(gray,(13,13),0)
blur8 = blur.astype(np.uint8)
canny=cv.Canny(blur8,110,120,3)
dilated=cv.dilate(canny,(-1,-1),iterations=2)
(cnt,heirarchy)=cv.findContours(dilated.copy(),cv.RETR_EXTERNAL,cv.CHAIN_APPROX_NONE)
rgb=cv.cvtColor(img,cv.COLOR_BGR2RGB)
cv.drawContours(rgb,cnt,-1,(0,255,0),2)

def find_contour_areas(cnt):
  areas=[]
  for contour in cnt:
    cont_area=cv.contourArea(contour)
    areas.append(cont_area)
  return areas

sorted_contours_by_area=sorted(cnt,key=cv.contourArea,reverse=True)

for sc in sorted_contours_by_area:
  duplicate_img=cv.imread(path,cv.IMREAD_UNCHANGED)
  #duplicate_img_color = cv.cvtColor(duplicate_img,cv.COLOR_GRAY2BGR)
  #cv.drawContours(duplicate_img_color,[sc],3)
  cv.drawContours(duplicate_img,3)
  cv.waitKey(0)
  cv2_imshow(duplicate_img)

cv.waitKey(0)

但结果是采用下图所示的形状：2 与人们第一眼看到的形状不完全相同。

有人可以帮我解决这个问题吗？提前致谢！