title: Difference between Low-Level and High-Level Feature Detection/ Extraction
body: <p>According to this Wikipedia article <a href="http://en.wikipedia.org/wiki/Feature_extraction" rel="noreferrer">Feature Extraction</a> examples for Low-Level algorithms are Edge Detection, Corner Detection etc.</p>
  
  <p>But what are High-Level algorithms?</p>
  
  <p>I only found this quote from the Wikipedia article <a href="http://en.wikipedia.org/wiki/Feature_detection_%28computer_vision%29" rel="noreferrer">Feature Detection (computer vision)</a>:</p>
  
  <blockquote>
    <p>Occasionally, when feature detection is computationally expensive and there are time constraints, a higher level algorithm may be used to guide the feature detection stage, so that only certain parts of the image are searched for features.</p>
  </blockquote>
  
  <p>Could you give an example of one of these higher level algorithms?</p>