title: Binarization of image in opencv
body: <p>I'm having a problem with binarization of image (perhaps blurry in general)
  I have this image:</p>
  
  <p><img src="https://i.stack.imgur.com/89ARr.jpg" alt=""></p>
  
  <p>and after I've done binarization I get</p>
  
  <p><img src="https://i.stack.imgur.com/XyfFv.png" alt=""></p>
  
  <p>How can I do better binarization? My goal is to have just black background and white letters and nothing else. I used adaptive threshold binarization</p>
  
  <pre><code>cv2.adaptiveThreshold(image_gs,255,cv2.ADAPTIVE_THRESH_MEAN_C,cv2.THRESH_BINARY ,41,3) 
  </code></pre>
  
  <p>and I also have </p>
  
  <pre><code>kernel=np.ones(1,1)
  </code></pre>
  
  <p>Does anyone have idea how to do that? </p>