/// Windows C# Sample Console Application: ImageAnalysis
///
/// ------------------------------------------------------------------------
///
/// Author: R.McAlister (2017)
///
/// ------------------------------------------------------------------------
///
/// This application demonstrates some of the functionality of the ccdsoftCamera and Image classes
///
/// The example takes a 60 second exposure then produces a recommendation window to display computed
/// optimal exposure length and duration for a one hour shoot, based on average background noise.
///
/// The algorithms are based on work by ...
/// John Smith: http://www.hiddenloft.com/notes/SubExposures.pdf
/// Charles Anstey: http://www.cloudynights.com/item.php?item_id=1622
/// Steve Cannistra: http://www.starrywonders.com/snr.html
///
/// Note: Where the required parameters like "gain" are not supplied through TSX, they are arbitrarily set for
/// an SBIG STF8300
///
public void ImageAnalysisSample()
{
///Open camera control and connect it to hardware
ccdsoftCamera tsx_cc = new ccdsoftCamera();
try {
tsx_cc.Connect();
}
catch {
MessageBox.Show("Camera Connect Error");
};
///turn on autosave
tsx_cc.AutoSaveOn = 1;
///Set for 60 second exposure, light frame with autodark
tsx_cc.ExposureTime = 60;
tsx_cc.Frame = ccdsoftImageFrame.cdLight;
tsx_cc.ImageReduction = ccdsoftImageReduction.cdAutoDark;
tsx_cc.FilterIndexZeroBased = 3; ///Assumed Lumescent, but change accordingly
tsx_cc.Delay = 5; ///Possible filter change = 5 sec delay
tsx_cc.Asynchronous = 1; ///Going to do a wait loop
tsx_cc.TakeImage();
while (tsx_cc.State == ccdsoftCameraState.cdStateTakePicture)
{
System.Threading.Thread.Sleep(1000);
}
;
///Create image object
ccdsoftImage tsx_im = new ccdsoftImage();
int imgerr = 0;
///Open the active image, if any
try {
imgerr = tsx_im.AttachToActive();
}
catch {
MessageBox.Show("No Image Available: " + imgerr.ToString());
return;
};
const int totalexp = 60; ///Minutes for total exposure sequence
double dGain = 0.37; ///electrons per ADU for SBIG STF8000M as spec///d
int iPedestal = 0; ///base pedestal
double dRnoise = 9.3; ///read out noise in electrons
double dNoiseFac = 0.05; ///maximum tolerable contribution of readout noise
double dExpFac = 1; ///Exposure reduction factor
double dSLambda = 15; ///Faint target ADU minimum
double dSNRMax = 0.9; ///fraction of maximum achievable signal to noise ratio (Cannistra)
///Presumably an Image Link has already been performed
///Check on this is TBD
int iPX = tsx_im.FITSKeyword("NAXIS1");
int iPY = tsx_im.FITSKeyword("NAXIS2");
int iPXBin = tsx_im.FITSKeyword("XBINNING");
int iPYBin = tsx_im.FITSKeyword("YBINNING");
///Dim igain as integer = tsx_im.FITSKeyword("EGAIN"); ///TSX doesn///t pick this up, yet
double dExpTime = tsx_im.FITSKeyword("EXPTIME");
iPX = iPX - 1;
iPY = iPY - 1;
double dAvgABU = tsx_im.averagePixelValue();
double dEsky = ((dAvgABU - iPedestal) * dGain) / dExpTime;
double dTorn = (System.Math.Pow(dRnoise, 2) / (((System.Math.Pow((1 + dNoiseFac), 2) - 1) * dEsky)));
///Smith algorithm
int iExp1 = (int)(dTorn / 2);
int iReps1 = (int)((((totalexp * 60) / dTorn) - 1) * 2);
///Anstey algorithm
int iExp2 = (int)((dSLambda * System.Math.Sqrt(totalexp * 60)) / (2 * System.Math.Sqrt(dAvgABU / dExpTime)));
int iReps2 = (int)((totalexp * 60) / iExp2);
///Cannestr algorithm
int iExp3 = (int)((System.Math.Pow(dSNRMax, 2) * System.Math.Pow(dRnoise, 2)) / ((dEsky) * (1 - System.Math.Pow(dSNRMax, 2))));
int iReps3 = (int)((totalexp * 60) / iExp3);
///Display Results
MessageBox.Show("Smith Model (at tolerable noise factor = 0.05):" + "\r\n" +
" " + iExp1.ToString() + " second exposure with" + "\r\n" +
" " + iReps1.ToString() + " repetitions per hour." + "\r\n" + "\r\n" +
"Anstey Model (at faint target minimum = 15):" + "\r\n" +
" " + iExp2.ToString() + " second exposure with" + "\r\n" +
" " + iReps2.ToString() + " repetitions per hour." + "\r\n" + "\r\n" +
"Cannestra Model (at SNR = 90% of maximum):" + "\r\n" +
" " + iExp3.ToString() + " second exposure with" + "\r\n" +
" " + iReps3.ToString() + " repetitions per hour.");
return;
}
public void ExposureAnalysis()
{
//Create image object
ccdsoftImage tsx_im = new ccdsoftImage();
int imgerr = 0;
//Open the active image, if any
try
{
imgerr = tsx_im.AttachToActiveImager();
}
catch
{
System.Windows.Forms.MessageBox.Show("No Image Available: " + imgerr.ToString());
return;
}
string resultstr;
int totalexp = 60; //Minutes for total exposure sequence
double gain = 0.37; //electrons per ADU for SBIG STF8000M as spec//d
double pedestal = 0; //base pedestal
double rnoise = 9.3; //read out noise in electrons
double noisefac = 0.05; //maximum tolerable contribution of readout noise
double slambda = 15; //Faint target ADU minimum
double snrtgt = 0.9; //fraction of maximum achievable signal to noise ratio (Cannistra)
int px;
int py;
int pxbin;
int pybin;
double exptime;
double avgABU;
double esky;
double torn;
int exp1;
int reps1;
int exp2;
int reps2;
int exp3;
int reps3;
//Presumably an Image Link has already been performed
//Check on this is TBD
px = tsx_im.FITSKeyword("NAXIS1");
py = tsx_im.FITSKeyword("NAXIS2");
pxbin = tsx_im.FITSKeyword("XBINNING");
pybin = tsx_im.FITSKeyword("YBINNING");
//gain = tsx_im.FITSKeyword("EGAIN");
exptime = tsx_im.FITSKeyword("EXPTIME");
px = px - 1;
py = py - 1;
avgABU = tsx_im.averagePixelValue();
esky = ((avgABU - pedestal) * gain) / exptime;
torn = Math.Pow(rnoise, 2) / ((Math.Pow((1 + noisefac), 2) - 1) * esky);
exp1 = (int)(torn / 2);
reps1 = (int)((((totalexp * 60) / torn) - 1) * 2);
exp2 = (int)((slambda * Math.Sqrt(totalexp * 60)) / (2 * Math.Sqrt(avgABU / exptime)));
reps2 = (int)((totalexp * 60) / exp2);
exp3 = (int)((Math.Pow(snrtgt, 2) * Math.Pow(rnoise, 2)) / ((esky) * (1 - Math.Pow(snrtgt, 2))));
reps3 = (int)((totalexp * 60) / exp3);
i_smith_exp = exp1;
i_smith_rep = reps1;
i_anstey_exp = exp2;
i_anstey_rep = reps2;
i_anstey_exp = exp3;
i_anstey_rep = reps3;
resultstr = ("Smith Model (at tolerable noise factor = 0.05):" + "\r\n" +
" " + exp1.ToString() + " second exposure with" + "\r\n" +
" " + reps1.ToString() + " repetitions per hour." + "\r\n" + "\r\n" +
"Anstey Model (at faint target minimum = 15):" + "\r\n" +
" " + exp2.ToString() + " second exposure with" + "\r\n" +
" " + reps2.ToString() + " repetitions per hour." + "\r\n" + "\r\n" +
"Cannestra Model (at SNR = 90% of maximum):" + "\r\n" +
" " + exp3.ToString() + " second exposure with" + "\r\n" +
" " + reps3.ToString() + " repetitions per hour.");
System.Windows.Forms.MessageBox.Show(resultstr, "Results", System.Windows.Forms.MessageBoxButtons.OK);
}