// This is an extended version of the Measure command
// that calculates object dispersion using the formula
// dispersion = 0.5(perimeter/sqrt(pi*area)).
//
// Thanks to Yaman al-Yousof

   setOption("Area", true);
   setOption("Perimeter", true);
   run("Measure");
   area = getResult("Area", nResults-1);
   perimeter = getResult("Perim.", nResults-1);
   dispersion = 0.5*perimeter/sqrt(PI*area);
   setResult('Dispersion', nResults-1, dispersion);
   updateResults();