title: Find known sub image in larger image
body: <p><strong>Does anyone know of an algorithm (or search terms / descriptions) to locate a known image within a larger image?</strong></p>
  
  <p>e.g.</p>
  
  <p>I have an image of a single desktop window containing various buttons and areas (target).  I also have code to capture a screen shot of the current desktop.  I would like an algorithm that will help me find the target image within the larger desktop image (what exact x and y coordinates the window is located at).  The target image may be located anywhere in the larger image and may not be 100% exactly the same (very similar but not exact possibly b/c of OS display differences)</p>
  
  <p>Does anyone know of such an algorithm or class of algorithms?</p>
  
  <p>I have found various image segmentation and computer vision algorithms but they seem geared to "fuzzy" classification of regions and not locating a specific image within another.</p>
  
  <p>** <em>My goal is to create a framework that, given some seed target images, can find "look" at the desktop, find the target area and "watch" it for changes.</em> **</p>