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Feature #12257

Updated by William Rice over 2 years ago

h1. Added roundness measurement to blobs 

 * Since we are trying to match a round template with round holes, the correlation shape should be round 
 * might be useful to add a measurement of how round the blobs are 
 * Leginon code had a "moment of inertia" measurement, but this was not really implemented and looks abandoned 
 * one measure of how round the object is uses area and perimeter: 
 <pre> 
   roundness = 4 pi * area / perimeter**2 
   for a circle, area = pi r**2 
   perimeter = 2 pi r, so perimeter**2 = 4 pi**2 r**2 
   and so perimeter**2 = 4 pi * area 
 </pre> 

 * needed to modify the following files 
 <pre> 
 pyami/imagefun.py 
 leginon/jahcfinder.py 
 leginon/jahcfinderback.py 
 leginon/jahcfindermodel.py 
 leginon/targetfinder.py 
 leginon/gui/wx/JAHCFinder.py 
 leginon/leginondata.py 
 </pre> 

 * perfect circle: 1.0 
 * square: 0.785 
 * line: approaches pi/len for large length: (pi * l)/(l**2 + 2l +1) 
 * need to see what is a good starting point is 0.8 
 * set to 0.3 or less to include virtually everything cutoff in practice 
 * implemented since October on Leginon at NYU

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