private void CalculateAndDisplayBackground(uint[,] backgroundPixels)
{
if (backgroundPixels != null)
{
int bgWidth = backgroundPixels.GetLength(0);
int bgHeight = backgroundPixels.GetLength(1);
var bgPixels = new List <uint>();
for (int x = 0; x < bgWidth; x++)
{
for (int y = 0; y < bgHeight; y++)
{
if (m_PSFFit == null || !m_PSFFit.IsSolved ||
ImagePixel.ComputeDistance(m_PSFFit.XCenter, x + bgWidth - m_PSFFit.MatrixSize, m_PSFFit.YCenter, y + bgHeight - m_PSFFit.MatrixSize) > 3 * m_PSFFit.FWHM)
{
bgPixels.Add(backgroundPixels[x, y]);
}
}
}
bgPixels.Sort();
double background = 0;
if (bgPixels.Count > 1)
{
background = m_Bpp < 12
? bgPixels[bgPixels.Count / 2] // for 8 bit videos Median background works better
: bgPixels.Average(x => x); // for 12+bit videos average background works better
}
double residualsSquareSum = 0;
foreach (uint bgPixel in bgPixels)
{
residualsSquareSum += (background - bgPixel) * (background - bgPixel);
}
double noise = Math.Sqrt(residualsSquareSum / (bgPixels.Count - 1));
lblBackground.Text = background.ToString("0.0");
lblNoise.Text = noise.ToString("0.0");
if (m_PSFFit != null)
{
double snr = m_PSFFit.GetSNR();
lblSNR.Text = snr.ToString("0.0");
}
else
{
lblSNR.Text = "N/A";
}
if (m_PSFFit != null)
{
lblFitVariance.Text = m_PSFFit.GetVariance().ToString("0.0");
lblFWHM.Text = m_PSFFit.FWHM.ToString("0.0");
}
else
{
lblFitVariance.Text = "N/A";
lblFWHM.Text = "N/A";
}
}
else
{
lblBackground.Text = "N/A";
lblNoise.Text = "N/A";
lblSNR.Text = "N/A";
}
}
internal NotMeasuredReasons DoOptimalExtractionPhotometry(
PSFFit fit,
uint[,] matrix, int x0Int, int y0Int, float x0, float y0,
float aperture, int matrixSize, bool isFullyDisappearingOccultedStar,
uint[,] backgroundArea,
bool mayBeOcculted /* Some magic based on a pure guess */,
double refinedFWHM, float bgAnnulusFactor)
{
// Proceed as with PSF Non linear, Then find the variance of the PSF fit and use a weight based on the residuals of the PSF fit
// Signal[x, y] = PSF(x, y) + weight * Residual(x, y)
double distance = ImagePixel.ComputeDistance(fit.XCenter, x0, fit.YCenter, y0);
double tolerance = isFullyDisappearingOccultedStar
? m_TimesHigherPositionToleranceForFullyOccultedStars * m_PositionTolerance
: m_PositionTolerance;
float psfBackground = (float)fit.I0;
// almost like aperture
if (matrix.GetLength(0) != 17 && matrix.GetLength(0) != 35)
{
throw new ApplicationException("Measurement error. Correlation: AFP-101B");
}
int side = matrix.GetLength(0);
float halfSide = side * 1f / 2f;
m_HasSaturatedPixels = false;
m_PSFBackground = double.NaN;
m_FoundBestPSFFit = null;
m_XCenter = x0 - x0Int + halfSide;
m_YCenter = y0 - y0Int + halfSide;
m_Aperture = aperture;
m_PixelData = matrix;
m_TotalPixels = 0;
double varR0Sq = fit.GetVariance();
varR0Sq = varR0Sq * varR0Sq * 2;
double deltaX = fit.X0_Matrix - m_XCenter;
double deltaY = fit.Y0_Matrix - m_YCenter;
m_TotalReading = GetReading(
m_Aperture,
m_PixelData, side, side,
m_XCenter, m_YCenter,
delegate(int x, int y)
{
double videoPixel = m_PixelData[x, y];
double psfValue = fit.GetValue(x + deltaX, y + deltaY);
if (fit.UsesBackgroundModel)
{
psfValue += fit.GetFittedBackgroundModelValue(x + deltaX, y + deltaY);
}
double residual = videoPixel - psfValue;
double weight = Math.Exp(-residual * residual / varR0Sq);
return(psfValue + residual * weight);
},
ref m_TotalPixels);
if (m_TotalPixels > 0)
{
if (m_BackgroundMethod == TangraConfig.BackgroundMethod.PSFBackground)
{
if (float.IsNaN(psfBackground))
{
m_TotalBackground = 0;
}
else
{
m_TotalBackground = (uint)Math.Round(m_TotalPixels * psfBackground);
}
}
else if (m_BackgroundMethod == TangraConfig.BackgroundMethod.Background3DPolynomial)
{
if (!fit.UsesBackgroundModel)
{
throw new InvalidOperationException("3D-Polynomial was not applied correctly.");
}
m_TotalBackground = Integration.IntegrationOverCircularArea(
(x, y) => fit.GetFittedBackgroundModelValue(x, y),
m_Aperture);
}
else if (m_BackgroundMethod != TangraConfig.BackgroundMethod.PSFBackground)
{
int offset = (35 - fit.MatrixSize) / 2;
double bgFromAnnulus = GetBackground(backgroundArea, m_Aperture, m_XCenter + offset, m_YCenter + offset, bgAnnulusFactor);
m_TotalBackground = (uint)Math.Round(m_TotalPixels * (float)bgFromAnnulus);
}
else
{
throw new ApplicationException("Measurement error. Correlation: AFP-102B");
}
if (!fit.IsSolved || // The PSF solution failed, mark the reading invalid
(distance > tolerance && !mayBeOcculted) || // If this doesn't look like a full disappearance, then make the reading invalid
(fit.FWHM < 0.75 * refinedFWHM || fit.FWHM > 1.25 * refinedFWHM) // The FWHM is too small or too large, make the reading invalid
)
{
return(!fit.IsSolved
? NotMeasuredReasons.MeasurementPSFFittingFailed
: (distance > tolerance && !mayBeOcculted)
? NotMeasuredReasons.DistanceToleranceTooHighForNonFullDisappearingOccultedStar
: NotMeasuredReasons.FWHMOutOfRange);
}
}
else
{
// We can't do much here, but this should never happen (??)
m_TotalBackground = 0;
m_TotalReading = 0;
return(NotMeasuredReasons.NoPixelsToMeasure);
}
return(NotMeasuredReasons.MeasuredSuccessfully);
}