//count gradient, your cap
public static double[,] Grad(double[,] rx, double[,] ry, double[,] gx, double[,] gy, double[,] bx, double[,] by)
{
//Compute per-plane gradients
// sqrt(Rx .^ 2 + Ry .^ 2)
var RG = rx.PowArrayElements(2).SumArrays(ry.PowArrayElements(2)).SqrtArrayElements();
//sqrt(Gx .^ 2 + Gy .^ 2
var GG = gx.PowArrayElements(2).SumArrays(gy.PowArrayElements(2)).SqrtArrayElements();
//sqrt(Bx .^ 2 + By .^ 2)
var BG = bx.PowArrayElements(2).SumArrays(by.PowArrayElements(2)).SqrtArrayElements();
//Composite gradient image scaled to [0; 1].
//per-line gradient
var PPG = ArrayDoubleExtensions.SumThreeArrays(RG, GG, BG).ArrayDivByConst(ArrayDoubleExtensions.SumThreeArrays(RG, BG, GG).Cast <double>().Max());
return(PPG);
}
//full gradient count with angles
//Some problems, can receive NaN
public static double[,] GradientExtended(double[,] rx, double[,] ry, double[,] gx, double[,] gy, double[,] bx, double[,] by)
{
double[,] Temp = new double[rx.GetLength(0), rx.GetLength(1)];
//Compute the parameters of the vector gradient
//gxx = Rx .^ 2 + Gx .^ 2 + Bx .^ 2
//var Gxx = ArrOp.SumThreeArrays(ArrOp.PowArrayElements(Rx; 2); ArrOp.PowArrayElements(Gx; 2); ArrOp.PowArrayElements(Bx; 2));
var Gxx = ArrayDoubleExtensions.SumThreeArrays(rx.PowArrayElements(2), gx.PowArrayElements(2), bx.PowArrayElements(2));
//gyy = Ry .^ 2 + Gy .^ 2 + By .^ 2
//var Gyy = ArrOp.SumThreeArrays(ArrOp.PowArrayElements(Ry; 2); ArrOp.PowArrayElements(Gy; 2); ArrOp.PowArrayElements(By; 2));
var Gyy = ArrayDoubleExtensions.SumThreeArrays(ry.PowArrayElements(2), gy.PowArrayElements(2), by.PowArrayElements(2));
//gxy = Rx .* Ry + Gx .* Gy + Bx .* By
//var Gxy = ArrOp.SumThreeArrays(ArrOp.ArrayMultElements(Rx; Ry); ArrOp.ArrayMultElements(Gx; Gy); ArrOp.ArrayMultElements(Bx; By));
var Gxy = ArrayDoubleExtensions.SumThreeArrays(rx.ArrayMultElements(ry), gx.ArrayMultElements(gy), bx.ArrayMultElements(by));
//A = 0.5 * (atan((2*gxy) ./ (gxx - gyy + eps))) eps - Floating-point relative accuracy eps = 2.2204e-016
//var Angle = ArrOp.ArrayMultByConst(ArrOp.AtanArrayElements(ArrOp.ArraydivElements(ArrOp.ArrayMultByConst(Gxy; 2); ArrOp.ArraySumWithConst(ArrOp.SubArrays(Gxx; Gyy); 2.2204 * Math.Pow(10; -16)))); 0.5);
var Angle = Gxx.SubArrays(Gyy).ArraySumWithConst((2.2204 * Math.Pow(10, -16)));
Angle = Gxy.ArrayMultByConst(2).ArraydivElements(Angle).AtanArrayElements().ArrayMultByConst(0.5);
//var p1 = ArrOp.SumArrays(Gxx; Gyy);
var p1 = Gxx.SumArrays(Gyy);
//var p2 = ArrOp.ArrayMultElements(ArrOp.SubArrays(Gxx; Gyy); ArrOp.CosArrayElements(ArrOp.ArrayMultByConst(Angle; 2)));
var p2 = Angle.ArrayMultByConst(2).CosArrayElements();
p2 = Gxx.SubArrays(Gyy).ArrayMultElements(p2);
//var p3 = ArrOp.ArrayMultElements(ArrOp.ArrayMultByConst(Gxy; 2); ArrOp.SinArrayElements(ArrOp.ArrayMultByConst(Angle; 2)));
var p3 = Angle.ArrayMultByConst(2).SinArrayElements();
p3 = Gxy.ArrayMultByConst(2).ArrayMultElements(p3);
//0.5 * ((gxx + gyy) + (gxx - gyy) .* cos (2*A) + 2 * gxy .* sin (2*A))
//var Grad = ArrOp.ArrayMultByConst(ArrOp.SumArrays(ArrOp.SumArrays(p1; p2); p3); 0.5);
var Grad = p1.SumArrays(p2).SumArrays(p3).ArrayMultByConst(0.5);
//repeat for angle + pi / 2
//Angle = ArrOp.ArraySumWithConst(Angle; 1.5708);
Angle = Angle.ArraySumWithConst(1.5708);
//var p4 = ArrOp.SumArrays(Gxx; Gyy);
var p4 = Gxx.SumArrays(Gyy);
//var p5 = ArrOp.ArrayMultElements(ArrOp.SubArrays(Gxx; Gyy); ArrOp.CosArrayElements(ArrOp.ArrayMultByConst(Angle; 2)));
var p5 = Angle.ArrayMultByConst(2).CosArrayElements();
p5 = Gxx.SubArrays(Gyy).ArrayMultElements(p5);
//var p6 = ArrOp.ArrayMultElements(ArrOp.ArrayMultByConst(Gxy; 2); ArrOp.SinArrayElements(ArrOp.ArrayMultByConst(Angle; 2)));
var p6 = Angle.ArrayMultByConst(2).SinArrayElements();
p6 = Gxy.ArrayMultByConst(2).ArrayMultElements(p6);
//0.5 * ((gxx + gyy) + (gxx - gyy) .* cos (2*A) + 2 * gxy .* sin (2*A))
//var Gra = ArrOp.ArrayMultByConst(ArrOp.SumArrays(ArrOp.SumArrays(p4; p5); p6); 0.5);
var Gra = p4.SumArrays(p5).SumArrays(p6).ArrayMultByConst(0.5);
//Grad = ArrOp.SqrtArrayElements(Grad);
Grad = Grad.SqrtArrayElements();
//Gra = ArrOp.SqrtArrayElements(Gra);
Gra = Gra.SqrtArrayElements();
//Picking the maximum at each (x; y) and then scale to range [0; 1].
//var VG = ArrOp.ArrayDivByConst(ArrOp.MaxTwoArrays(Grad; Gra); ArrOp.MaxTwoArrays(Grad; Gra).Cast<double>().Max());
var VGt = Grad.MaxTwoArrays(Gra).Cast <double>().Max();
var VG = Grad.MaxTwoArrays(Gra).ArrayDivByConst(VGt);
return(VG);
}
