public virtual void UpdateScan(double[] rampData, double[] scanData, bool shouldBlock)
{
LatestScanData = scanData;
lockBlocked = shouldBlock;
if (!lockBlocked)
{
switch (lState)
{
case LaserState.LOCKED:
LorentzianFit newFit = FitWithPreviousAsBestGuess(rampData, scanData);
double dataPeakCentre = rampData[Array.IndexOf(scanData, scanData.Max())];
bool fitTooNarrow = newFit.Width < 0.001; // Sometimes fit seems to break and give a tiny width
bool fitTooFarFromMax = Math.Abs(newFit.Centre - dataPeakCentre) / newFit.Width > 1;
if (fitTooNarrow || fitTooFarFromMax)
{
newFit = FitUsingDataForBestGuess(rampData, scanData);
}
Fit = newFit;
break;
case LaserState.LOCKING:
Fit = FitUsingDataForBestGuess(rampData, scanData);
Lock();
break;
case LaserState.FREE:
break;
}
}
}
protected LorentzianFit FitUsingDataForBestGuess(double[] rampData, double[] scanData)
{
double background = scanData.Min();
double maximum = scanData.Max();
double amplitude = maximum - background;
double centre = rampData[Array.IndexOf(scanData, maximum)];
double width = (rampData.Max() - rampData.Min()) / 20;
LorentzianFit bestGuessFit = new LorentzianFit(background, amplitude, centre, width);
return(CavityScanFitHelper.FitLorentzianToData(rampData, scanData, bestGuessFit));
}
private static LorentzianFit fitFailSafe(LorentzianFit fit, double lowerLimit, double upperLimit)
{
if (fit.Centre < lowerLimit)
{
fit.Centre = lowerLimit;
}
else if (fit.Centre > upperLimit)
{
fit.Centre = upperLimit;
}
return(fit);
}
public static LorentzianFit FitLorentzianToData(double[] voltages, double[] signal, LorentzianFit bestGuess)
{
LorentzianFitter lorentzianFitter = new LorentzianFitter();
lorentzianFitter.Fit(voltages, signal, new double[] { bestGuess.Background, bestGuess.Amplitude, bestGuess.Centre, bestGuess.Width });
double[] coefficients = lorentzianFitter.Parameters;
LorentzianFit fit = new LorentzianFit(coefficients[0], coefficients[1], coefficients[2], coefficients[3]);
double minCentrePosition = voltages.Min();
double maxCentrePosition = voltages.Max();
fit = fitFailSafe(fit, minCentrePosition, maxCentrePosition);
return(fit);
}
/// <summary>
/// A helper function. generates a bunch of points from a some fit coefficients.
/// </summary>
/// <param name="cavityVoltages"></param>
/// <param name="fitCoefficients"></param>
/// <returns></returns>
public static double[] CreatePointsFromFit(double[] cavityVoltages, LorentzianFit fit)
{
double[] fitPoints = new double[cavityVoltages.Length];
double n = fit.Background;
double q = fit.Amplitude;
double c = fit.Centre;
double w = fit.Width;
for (int i = 0; i < cavityVoltages.Length; i++)
{
if (w == 0)
{
w = 0.001; // watch out for divide by zero
}
fitPoints[i] = n + q * (1 / (1 + (((cavityVoltages[i] - c) * (cavityVoltages[i] - c)) / ((w / 2) * (w / 2)))));
}
return(fitPoints);
}
