title: how to find the template matching accuracy
body: <p>i am doing a template matching<br>
  now,what i want to do is find the accuracy of template matching<br>
  I have done template matching, but how do i get the accuracy
  i think i have to subtract the matched region and template image.
  how do i achieve this </p>
  
  <p><strong>CODE</strong></p>
  
  <pre><code>import cv2 as cv
  import numpy as np
  import matplotlib.pyplot as plt
  
  img = cv.imread('image.jpg',0)
  img1 = img.copy()
  template = cv.imread('template.jpg',0)
  w, h = template.shape[::-1]
  
  method = ['cv.TM_CCOEFF_NORMED','cv.TM_CCORR_NORMED']
  for meth in method:
      img = img1.copy()
      method = eval(meth)
  
      res = cv.matchTemplate(img,template,method)
      min_val, max_val, min_loc, max_loc = cv.minMaxLoc(res)
  
      bottom_right = (top_left[0] + w, top_left[1] + h)
      cv.rectangle(img,top_left, bottom_right, 255, 2)
      plt.subplot(121)
      plt.imshow(res,cmap = 'gray')
      plt.title('Matching Result')
  
      plt.subplot(122)
      plt.imshow(img,cmap = 'gray')
      plt.title('Detected Point') 
      plt.show()
  </code></pre>