title: How to change invert frames in EmguCV?
body: <p>Currently, I am working on a real-time IRIS detection application.</p>
  
  <p>I want to perform an invert operation to the frames taken from the web camera, like this:</p>
  
  <p><img src="https://i.stack.imgur.com/jamOe.png" alt="enter image description here"></p>
  
  <p>I managed to get this line of code, but this is not giving the above results. Maybe parameters need to be changed, but I am not sure.</p>
  
  <pre><code>CvInvoke.cvThreshold(grayframeright, grayframeright, 160, 255.0, Emgu.CV.CvEnum.THRESH.CV_THRESH_BINARY_INV);
  </code></pre>