public static double ChiSquare ( double [ ] histogram1 , double [ ] histogram2 ) { double r = 0 ; for ( int i = 0 ; i < histogram1 . length ; i ++ ) { double t = histogram1 [ i ] + histogram2 [ i ] ; if ( t != 0 ) r += Math . pow ( histogram1 [ i ] - histogram2 [ i ] , 2 ) / t ; } return 0.5 * r ; }
Gets the Chi Square distance between two normalized histograms .