private bool degenerate(int[] points)
{
PointF[] x1 = this.pointSet1.Get(points);
PointF[] x2 = this.pointSet2.Get(points);
// If any three of the four points in each set is collinear,
// the resulting homography matrix will be degenerate.
return Tools.Collinear(x1[0], x1[1], x1[2]) ||
Tools.Collinear(x1[0], x1[1], x1[3]) ||
Tools.Collinear(x1[0], x1[2], x1[3]) ||
Tools.Collinear(x1[1], x1[2], x1[3]) ||
Tools.Collinear(x2[0], x2[1], x2[2]) ||
Tools.Collinear(x2[0], x2[1], x2[3]) ||
Tools.Collinear(x2[0], x2[2], x2[3]) ||
Tools.Collinear(x2[1], x2[2], x2[3]);
}