title: What happens when show a signed image in OpenCV?
body: <p>The documentation of <code>imshow</code> only writes:</p>
  
  <blockquote>
    <ul>
    <li>If the image is 8-bit unsigned, it is displayed as is.</li>
    <li>If the image is 16-bit unsigned or 32-bit integer, the pixels are divided by 256. That is, the value range [0,255*256] is mapped to [0,255].</li>
    <li>If the image is 32-bit floating-point, the pixel values are multiplied by 255. That is, the value range [0,1] is mapped to [0,255].</li>
    </ul>
  </blockquote>
  
  <p>No define behavior about signed image.</p>