title: How to segment region of interest in a leaf image
body: <p><strong>Objective:</strong>
  I want to detect certain regions of the leaf images.
  I've found related problems of mine, close to which is this <a href="https://stackoverflow.com/questions/21619604/segment-objectleaf-which-is-on-the-white-paper-using-image-processing">segment object(leaf) which is on the white paper using image processing</a> (removing leaf from white background) but mine goes beyond it, it aims to extract/segment the diseased area of the leaf.</p>
  
  <p><strong>Problem:</strong>
  How to accurately segment and extract the diseased areas of the leaf in the image.</p>
  
  <p><strong>My attempt:</strong><br>
  1. <em>inRange() OpenCV function</em>
      -Threshold green color so that I won't be making several inRange values for non-green areas(brown, gray,etc) and I will remove the green color hopefully; I applied Gaussian blur, converted from RGB to HSV before segmenting</p>
  
  <p><strong>Link to Files</strong> of image1, image2 input and results: <br>
  <strong>Image1:</strong> 
  <strong><em>Result:</em></strong> Green was segmented(thought not quite accurately), but I still don't know how to extract the non-green areas(as the next step)</p>
  
  <p><strong>Image2:</strong>
  <strong><em>Result:</em></strong> The dark small circles were included/considered green which supposedly should not<br></p>
  
  <p>I am new to OpenCV(and also C++) and I have read several techniques(like clustering methods fuzzy-c and k-means, etc) for segmentation but I can't decide which segmentation technique to use for my images. I've also learned from the articles I read that there's no such thing as universal segmentation technique that can be applied to all images.</p>
  
  <p>Thus, I would like to know which technique(clustering method? region based? histogram?, etc)  or process is best to apply for the kinds of images I have in order to accurately segment said images.</p>
  
  <p>Thank you very much.</p>