title: Tesseract can't recognize image after Clearing image incomprehensibly
body: <p>I want to ocr two-digit-image after erasing right number for good accuracy. 
  Example) <a href="http://i.stack.imgur.com/NA2WK.png" rel="nofollow">Original</a>, <a href="http://i.stack.imgur.com/rKrPn.png" rel="nofollow">Modified</a></p>
  
  <p>The image is PNG file(52*26px) and background color is (192,192,192,255) and color of each digit is different.</p>
  
  <p>But amazingly after erasig right number, tesseract cannot recognize the number.</p>
  
  <p>Result:</p>
  
  <pre><code>original:60
  left:
  </code></pre>
  
  <hr>
  
  <pre><code>from PIL import Image
  from pytesseract.pytesseract import *
  
  im=Image.open('NA2WK.png')
  
  #calculate far left xpos of color
  color={}
  for i in range(52):
      for j in range(26):
          if im.load()[i,j]!=(192,192,192,255):
              if color.get(im.load()[i,j])==None:
                  color[im.load()[i,j]]=9999
              if i&lt;color[im.load()[i,j]]: 
                  color[im.load()[i,j]]=i
  
  #get color of left character
  if color.values()[0]&lt;color.values()[1]:
      left=color.keys()[0]
      right=color.keys()[1]
  else:
      left=color.keys()[1]
      right=color.keys()[0]   
  
  #left processing
  imleft=Image.open('test.png')
  pix=imleft.load()
  for i in range(52):
      for j in range(26):
          if pix[i,j]==(192,192,192,255) or pix[i,j]==right:
              pix[i,j]=(255,255,255,255)
          else:
              pix[i,j]=(0,0,0,255)
  
  print('original:'+image_to_string(im))
  print('left:'+image_to_string(imleft))
  </code></pre>