title: What's the rule stretched arabic letter is used in real video subtile generation?
body: <p>I have some problem when synthetic arabic text image. In order to make good arabic text recognition, the synthetic image must be similar to the real video text image as max as possible.</p>
  
  <p><a href="https://i.stack.imgur.com/ebz3T.png" rel="nofollow noreferrer">synthetic image</a></p>
  
  <p><a href="https://i.stack.imgur.com/FqZSY.png" rel="nofollow noreferrer">real video image</a></p>
  
  <p>As you can see, some real video images may have stretched some arabic letters use u0640. So I think I should add some u0640 in my synthetic text characters to get the similar effect. But I don't know what's the rule when u0640 is used in real video arabic images. Is there anyone have some advices ?</p>
  
  <p>And I also found there are two problems in adding u0640. </p>
  
  <ol>
  <li><p>the number of \u0640 between two connected arabic letters is just one, or two, or three ? </p>
  
  <p><a href="https://i.stack.imgur.com/k4G9C.jpg" rel="nofollow noreferrer">not add u0640</a></p>
  
  <p><a href="https://i.stack.imgur.com/I8gOH.jpg" rel="nofollow noreferrer">add one u0640</a></p>
  
  <p><a href="https://i.stack.imgur.com/1eO4y.jpg" rel="nofollow noreferrer">add two u0640</a></p></li>
  <li><p>If the picture have some words use u0640, does the number of \u0640 between each pair connected arabic letters are the same ?</p></li>
  </ol>
  
  <p>What's the rule when video caption were pasted to the background image ? How can I simulate the effect of the real video image with \u0640 as most as possible ? 
  Thank you very much.</p>