title: OpenCV Python equalizeHist colored image
body: <p>I need to do a histogram equalization for a colored image.</p>
  
  <p>First I convert the colored image to gray and give it to the <code>equalizeHist</code> function:</p>
  
  <pre><code>image = cv2.imread("photo.jpg")
  image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
  cv2.equalizeHist(image)
  cv2.imshow("equalizeHist", image)
  cv2.waitKey(0)
  </code></pre>
  
  <p>But after this I need to convert the image back to RGB; how can i do that?</p>