Hi Haiyong,<br>itk::ImageRegion has a crop function that will return the intersecting area of two regions:<br><br>itk::ImageRegion regionOne = imageOne->GetLargestPossibleRegion();<br>itk::ImageRegion regionTwo = imageTwo->GetLargestPossibleRegion();<br>
<br>regionOne.Crop(regionTwo);<br><br>If you feed the regions progressively into this pseudo-code you will end up with the common region. Use image iterators to access this common region and create a new image of the average.<br>
<br>I also found this<br><a href="http://www.vtk.org/Wiki/ITK/Examples/SimpleOperations/RegionOverlap">http://www.vtk.org/Wiki/ITK/Examples/SimpleOperations/RegionOverlap</a><br>which may help.<br><br>Cheer,<br>Seth <br><br>
<br>