docs: public double computeConfidence( int x0 , int y0 , int x1 , int y1 ) {
  
  		computeNccDescriptor(observed,x0,y0,x1,y1);
  
  		// distance from each set of templates
  		if( templateNegative.size() > 0 && templatePositive.size() > 0 ) {
  			double distancePositive = distance(observed,templatePositive);
  			double distanceNegative = distance(observed,templateNegative);
  
  			return distanceNegative/(distanceNegative + distancePositive);
  		} else if( templatePositive.size() > 0 ) {
  			return 1.0-distance(observed,templatePositive);
  		} else {
  			return distance(observed,templateNegative);
  		}
  	}