title: How to check color-uniformity of a region?
body: <p>I'm trying to check the homogeneity in pixel values over a small region in an image - e.g. A  word or a letter. However when taking the greyvalues of RGB, there is a lot of variance in values even between image patches that seem to have uniform color to the human eye.</p>
  
  <p>Looking for a color-space that will be able to negate this variation if the difference in color is perceptually too little. Tried the L<em>a</em>b and HSV color spaces. They all work for a few cases, but often false colors come up in places of uniform color. Any suggestions?</p>
  
  <p>Thanks.</p>
  
  <p><strong>EDIT:</strong> (sample images from the ICDAR dataset. running tests on those)</p>
  
  <p><img src="https://i.stack.imgur.com/5AMxC.jpg" alt="Hue channel from HSV"></p>
  
  <p><img src="https://i.stack.imgur.com/zaSQc.jpg" alt="Original RGB image"></p>