public SizeF GetSize()
{
// Compute the covariance matrix
//
double a = Mu20 * invM00; // | a b |
double b = Mu11 * invM00; // Cov[I(x,y)] = | |
double c = Mu02 * invM00; // | b c |
double d = a + c, e = a - c;
double s = Math.Sqrt((4.0 * b * b) + (e * e));
// Compute size
return new SizeF((float)Math.Sqrt((d - s) * 0.5) * 4,
(float)Math.Sqrt((d + s) * 0.5) * 4);
}
public void ComputeTest()
{
Bitmap image = Resources.hu;
CentralMoments target = new CentralMoments(image, order: 3);
Assert.AreEqual(86424.0 / target.Mu00, 1);
Assert.AreEqual(0, target.Mu01);
Assert.AreEqual(0, target.Mu10);
Assert.AreEqual(5.868206472635379E8 / target.Mu02, 1, 1e-2);
Assert.AreEqual(6348920.945848465 / target.Mu11, 1, 1e-2);
Assert.AreEqual(9.084235762166061E8 / target.Mu20, 1, 1e-3);
Assert.AreEqual(-2.155191E9 / target.Mu12, 1, 1e-5);
Assert.AreEqual(7.125893E8 / target.Mu21, 1, 1e-3);
Assert.AreEqual(-1.26244547E10 / target.Mu30, 1, 1e-8);
Assert.AreEqual(1.71818829E9 / target.Mu03, 1, 1e-8);
SizeF size = target.GetSize();
float angle = target.GetOrientation();
Assert.AreEqual(410.207916f, size.Height);
Assert.AreEqual(329.534637f, size.Width);
Assert.AreEqual(0.0196384024f, angle);
}