title: Multi-class image classification with probability estimation
body: <p>my goal is to do multi-class image classification with probability estimation. </p>
  
  <p>So far the 'one-label'-classification is working nicely out-of-the-box with all the great functionalities the OpenCV C++ libraries provide. Currently I am using a BoW descriptor with local Sift descriptors and SVM classification. So far so good. But now I need probability estimates for the images. So instead of "image A is class X", <strong>I need the output "image A is with 50% likelihood class X, with 10% class Y, 30% class Z"</strong>, etc. with estimations for all classes.</p>
  
  <p>Unfortunately I am not that competent in machine learning. I started to investigate the problem and now my brain hurts. My noob-questions for you:</p>
  
  <ul>
  <li>Is the libsvm option <code>-b probability_estimates</code> what I am looking for?</li>
  <li>Is there a way to do this solely with OpenCV? (If <a href="https://stackoverflow.com/questions/19810228/get-svm-classification-score-in-multiclass-classification-with-opencv">Get SVM classification score in multiclass classification with OpenCV</a> is the only way, could someone explain the output to me?)</li>
  <li>Do you have any other suggestions on how to achieve my goal? Papers to read, libraries to use?</li>
  </ul>
  
  <p>Any tips are appreciated. Thanks!</p>
  
  <p>P.S.: I know there are a bunch of similar questions answered here before but to me none of them really captured my point.</p>