public static bool AttachFitsFile(ccdsoftImage tsximg)
{
try { tsximg.AttachToActive(); }
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return(false);
}
return(true);
}
private bool OptimizeExposure(double maxExposure)
{
//Subframe size
const int subFrameSize = 192;
//Subframe the center in order to get rid of any brighter outliers
const int testExposure = 10;
const double minExposure = 0.1;
ccdsoftImage tsxi = new ccdsoftImage();
tsxi.AttachToActive(); //We should have a CLS image handy
double xcenter = tsxi.WidthInPixels / 2;
double ycenter = tsxi.HeightInPixels / 2;
//Set up 64 pixel square subframe
int subTop = (int)ycenter - subFrameSize / 2; //Y is top down
int subBottom = (int)ycenter + subFrameSize / 2; //Y is top down
int subRight = (int)xcenter + subFrameSize / 2;
int subLeft = (int)xcenter - subFrameSize / 2;
Configuration cfg = new Configuration();
int ADUMax = Convert.ToInt32(cfg.ADUMax);
ccdsoftCamera tsx_cc = new ccdsoftCamera
{
AutoSaveOn = 0, //Autosave Off
FilterIndexZeroBased = freshImageFilter,
ExposureTime = testExposure,
Subframe = 1,
SubframeTop = subTop,
SubframeBottom = subBottom,
SubframeLeft = subLeft,
SubframeRight = subRight,
Frame = ccdsoftImageFrame.cdLight,
ImageReduction = ccdsoftImageReduction.cdAutoDark,
Asynchronous = 0 //Asynchronous off for this short shot
};
do
{
tsx_cc.TakeImage();
double maxPixel = tsx_cc.MaximumPixel;
double correctExposure = (ADUMax / maxPixel) * tsx_cc.ExposureTime;
if (correctExposure > maxExposure)
{
correctExposure = maxExposure;
}
freshImageExposure = correctExposure;
if (maxPixel > ADUMax)
{
tsx_cc.ExposureTime = freshImageExposure;
}
} while (tsx_cc.MaximumPixel > ADUMax && freshImageExposure > minExposure);
return(true);
}
/// 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;
}