title: How to train HOG and use my HOGDescriptor?
body: <p>I want to training data and use HOG algorithm to detect pedestrian.
  Now I can use <code>defaultHog.setSVMDetector(HOGDescriptor::getDefaultPeopleDetector());</code> in <code>opencv</code> to detection, but the result is not very good to my testing video. So I want to do training use my database.</p>
  
  <p>I have prepared 1000+ positive sample, and 1000+ negative samples. They are cropped to size 50 * 100, and I have do the list file.</p>
  
  <p>And I have read some tutorials on the internet, they all so complex, sometimes abstruse. Most of them are analyze the source code and the algorithm of HOG. But with only less examples and simple anylize. </p>
  
  <p>Some instruction show that <code>libsvm\windows\svm-train.exe</code> can be used to training, Can anyone gives an examples according to 1000+ 50*100 positive samples?<br>
  For example, like <code>haartraing</code>, we can do it from <code>opencv</code>, like <code>haartraining.exe –a –b</code> with some parameters, and get a <code>*.xml</code> as a result which will be used to people detection?</p>
  
  <p>Or is there any other method to training, and detection?</p>
  
  <p>I prefer to know how to use it and the detail procedures. As the detail algorithm, it is not important to me. I just want to implement it.</p>
  
  <p>If anyone know about it, please give me some tips.</p>