private double GaussianDirection(Minutia middleMinutia, Minutia minutia, double anglePoint) { double common = Math.Sqrt(2) * SigmaDirection; double angle = CylinderHelper.GetAngleDiff(anglePoint, CylinderHelper.GetAngleDiff(middleMinutia.Angle, minutia.Angle)); double first = Erf(((angle + HeightCell / 2)) / common); double second = Erf(((angle - HeightCell / 2)) / common); return((first - second) / 2); }