/// <summary>
/// Create a DiffusionParameters object from OpticalProperties object and a ForwardModel
/// choice.
/// </summary>
/// <param name="op">OpticalProperties object</param>
/// <param name="fm">ForwardModel enum</param>
/// <returns>new DiffusionParameters object</returns>
public static DiffusionParameters Create(OpticalProperties op, ForwardModel fm)
{
var mua = op.Mua;
var mutr = op.Mua + op.Musp;
var cn = GlobalConstants.C / op.N;
var D = 1 / (3 * mutr);
var A = CalculatorToolbox.GetCubicAParameter(op.N);
var mueff = Math.Sqrt(3 * op.Mua * mutr);
var zb = 2 / (3 * mutr) * A;
double musTilde;
double gTilde;
switch (fm)
{
case ForwardModel.SDA:
default:
musTilde = op.Musp;
gTilde = op.G;
break;
case ForwardModel.DeltaPOne:
musTilde = op.Musp * (1 - op.G * op.G) / (1 - op.G);
gTilde = op.G / (op.G + 1);
break;
}
var mutTilde = op.Mua + musTilde;
var zp = 1 / mutTilde;
return(new DiffusionParameters(A, mueff, zb, zp, mutTilde, musTilde, mutr, gTilde, D, cn, mua));
}
/// <summary>
/// Modulation frequency-dependent reflectance. Modified from Pham et al, Appl. Opt. Sept 2000
/// to include spatial modulation, as described in Cuccia et al, J. Biomed. Opt. March/April 2009
/// </summary>
/// <param name="op">optical properties of the medium</param>
/// <param name="fx">spatial frequency</param>
/// <param name="ft">modulation frequency (GHz)</param>
/// <returns></returns>
public override Complex ROfFxAndFt(OpticalProperties op, double fx, double ft)
{
double A = CalculatorToolbox.GetCubicAParameter(op.N);
double wOverC = Math.PI * ft * op.N / GlobalConstants.C;
double mutr = op.Mua + op.Musp;
Complex D = 1 / (3 * mutr * (1.0 + Complex.ImaginaryOne * wOverC / mutr));
Complex mueff =
(
3.0 * op.Mua * mutr -
3.0 * wOverC * wOverC +
Complex.ImaginaryOne * (1 + op.Mua / mutr) * 3.0 * mutr * wOverC +
4.0 * Math.PI * Math.PI * fx * fx
).SquareRoot();
Complex temp = mueff * D;
return(3 * A * op.Musp * D / (temp + 1.0 / 3.0) / (temp + A));
}