title: How to identify if the shapes of an image are symmetric or asymmetric using opencv - python?
body: <p>I'm working on the extraction of image characteristics, in which I'm trying to identify if a certain image is symmetric or not. I am using opecv - python for the development of this work.</p>
  
  <p>The code below is used to identify the center and the diameter of the region of interest. How could you know if this image is symmetrical or not?</p>
  
  <pre><code>import cv2
  import numpy as np
  import matplotlib.pyplot as plt
  from matplotlib.offsetbox import AnchoredText
  
  IMG = '015'
  thresh = cv2.imread(IMD+'.png',0)
  _, contours,hierarchy = cv2.findContours(thresh,2,1)
  print (len(contours))
  cnt = contours
  
  for i in range (len(cnt)):
      (x,y),radius = cv2.minEnclosingCircle(cnt[i])
      center = (int(x),int(y))
      radius = int(radius)
      cv2.circle(thresh,center,radius,(0,255,0),2)
      print ('Circle: ' + str(i) + ' - Center: ' + str(center) + ' - Radius: ' + str(radius))
  plt.text(x-21, y+15, '+', fontsize=25, color = 'red')
  plt.text(10, -10, 'Centro: '+str(center), fontsize=11, color = 'red')
  plt.text(340, -10, 'Diametro: '+str((radius*2)/100)+'mm', fontsize=11,     color = 'red')
  plt.Circle((10, -10), 7.2, color='blue')
  plt.imshow(thresh, cmap='gray')
  #plt.savefig(IMG+'-diam.png')
  plt.show()
  </code></pre>
  
  <p>exit:
  <a href="https://i.stack.imgur.com/PlQ2F.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PlQ2F.png" alt="enter image description here"></a></p>
  
  <p>In the case, I am wanting to classify if the spot I am analyzing is symmetric or not, the image below, visually it is noted that it is not symmetrical, while the first image of the above plot is symmetrical.</p>
  
  <p><a href="https://i.stack.imgur.com/0tyq7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/0tyq7.png" alt="enter image description here"></a></p>