title: Python, Numpy, replace certain values in an image
body: <p>I'm looking for an efficient way to replace certain values within a numpy image.
  So far this is where I got :</p>
  
  <pre><code>def observation(self, img):
      # 45 50 184
      background = np.array([45, 50, 184])
      # 80 0 132
      border = np.array([80, 0, 132])
      img = self.crop(img)
      for line_index, line in enumerate(img):
          for pixel_index, pixel in enumerate(line):
              if not np.array_equal(pixel, background) and not np.array_equal(pixel, border):
                  img[line_index][pixel_index] = [254, 254, 254]
  </code></pre>
  
  <p>The idea is to replace all the colors that are not background or border to white.
  I'm quite new to this, so I'm fairly sure that there is a more efficient way to do this.</p>
  
  <p>Thanks all.</p>