BeamSplitterFit

java.lang.Object
- stella.util.BeamSplitterFit

All Implemented Interfaces:

Multidimensional
```
public class BeamSplitterFit
extends Object
implements Multidimensional
```
This class tries to fit data from the guider ccd to a double-peaked gaussian to resemble the STELLA-I guiding setup. The function fitted reads as
```
 f(x,y) = I_0·exp(-((x-x_0)²+(y-y_0)²)/2σ_0²+
      k_I I_0·exp(-((x-x_0-Δx)²+(y-y_0-Δy)²)/2σ_0²·k_s²+sky;
 
```
The values fitted are I_0, x_0, y_0, σ_0, k_I, k_s, and Δx, Δy, which are the peak intensity and the peak center on the CCD, the peak width, the offset of the secondary peak in Δx,y and the realative intensity k_I and relative width k_s. It is guaranteed, that Δx and Δy are constant and also k_I and k_s should not vary. So, determining these coefficients once leaves only four parameter that vary from frame to frame. The Δx Δy and k's might also be used for fitting the star plus the hole, with signs on Δ's reversed. Solving for the parameters is done with a simplex method. For each x/y coordinate pair, the function above is evaluated, the difference to the counts is calculated and squared and the squared difference is weighed with a poisson noise plus a readout noise. The sky value is estimated from the median of the outermost pixel.

Field Summary

Fields
Modifier and Type	Field and Description
`private int[][]`	`counts` The count arra, normally deduced from a fits file, x is first index.
`private double`	`deltax` On declaring hole fitting, we set the binning factor and get deltax.
`static double`	`DELTAX` After averaging some non-pinhole images, the secondary peak offset.
`private double`	`deltay` On declaring hole fitting, we set the binning factor and get deltax.
`static double`	`DELTAY` The average secondary peak offset in the mirror.
`static double`	`FWHMMIRROR` The average fwhm factor between direct and mirror in best focus.
`private boolean`	`hole` If this is true, we fit to double gauss plus pinhole.
`static double`	`IMIRROR` The average intensity factor between the direct and the mirror image.
`private double`	`intensity` On hole fitting, we set the direct intensity and get the mirror i.
`static double`	`KI` The average intensity factor of the secondary peak.
`static double`	`KS` The average fwhm relation between primary and secondary peak.
`private double`	`sigma` On hole fitting, we set the direct fwhm and get the mirror sigma.
`private double`	`sky` The sky count.
`private double[][]`	`weight` The weight of each pixel, calculateed from readout noise and Poisson.

Constructor Summary

Constructors
Constructor and Description
`BeamSplitterFit(int[][] ccd, double gain, double readout, boolean weigh)` Constructs a new beam splitter that can readily be used for Amoeba.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int`	`dimension()` Returns 8 for normal fits, 6 for pinhole fits.
`private double`	`evaluate(VectorG fit, boolean print)` Evaluates the functional fit.
`void`	`evaluateHole(int binx, int biny, double idirect, double fwhmdirect)` If we want to fit the double gaussian and the pinhole as negative gaussian, we can do that here.
`double`	`evaluateWithNan(VectorG fit)` Evaluates the functional fit.
`private static double`	`gauss(double i0, double x, double y, double sig)` Calculates a two-dimensional gauss.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - DELTAX
```
public static final double DELTAX
```
    After averaging some non-pinhole images, the secondary peak offset.
    
    See Also:
    
    Constant Field Values
  - DELTAY
```
public static final double DELTAY
```
    The average secondary peak offset in the mirror.
    
    See Also:
    
    Constant Field Values
  - KI
```
public static final double KI
```
    The average intensity factor of the secondary peak.
    
    See Also:
    
    Constant Field Values
  - KS
```
public static final double KS
```
    The average fwhm relation between primary and secondary peak.
    
    See Also:
    
    Constant Field Values
  - IMIRROR
```
public static final double IMIRROR
```
    The average intensity factor between the direct and the mirror image.
    
    See Also:
    
    Constant Field Values
  - FWHMMIRROR
```
public static final double FWHMMIRROR
```
    The average fwhm factor between direct and mirror in best focus.
    
    See Also:
    
    Constant Field Values
  - counts
```
private int[][] counts
```
    The count arra, normally deduced from a fits file, x is first index.
  - weight
```
private double[][] weight
```
    The weight of each pixel, calculateed from readout noise and Poisson.
  - sky
```
private double sky
```
    The sky count.
  - hole
```
private boolean hole
```
    If this is true, we fit to double gauss plus pinhole.
  - deltax
```
private double deltax
```
    On declaring hole fitting, we set the binning factor and get deltax.
  - deltay
```
private double deltay
```
    On declaring hole fitting, we set the binning factor and get deltax.
  - intensity
```
private double intensity
```
    On hole fitting, we set the direct intensity and get the mirror i.
  - sigma
```
private double sigma
```
    On hole fitting, we set the direct fwhm and get the mirror sigma.
- Constructor Detail
  - BeamSplitterFit
```
public BeamSplitterFit(int[][] ccd,
                       double gain,
                       double readout,
                       boolean weigh)
```
    Constructs a new beam splitter that can readily be used for Amoeba.
- Method Detail
  - evaluateHole
```
public void evaluateHole(int binx,
                         int biny,
                         double idirect,
                         double fwhmdirect)
```
    If we want to fit the double gaussian and the pinhole as negative gaussian, we can do that here. First test showed too high error if we also fit the height and with of the mirror star, but from comparison with non-pinhole affected images, we can derive the mirror intensity and the mirror fwhm from first solving on the direct image, then multiplying the intensity and fwhm of the direct image with IMIRROR and FWHMMIRROR, respectively. In this method, we have to give the intensity and the fwhm of the direct solution.
  - evaluateWithNan
```
public double evaluateWithNan(VectorG fit)
```
    Evaluates the functional fit. The vector passed over must have a dimensionality of nine and must provide the data in the following form, ordered by index number.
    - Intesity maximum of the brighter peak
    - pixel-x of intensity maximum.
    - pixel-y of intensity maximum.
    - sigma of intensity in pixel
    - relative intensity of secondary peak
    - delta-x of secondary peak
    - delta-y of secondary peak
    - relative scaling of fwhm of secondary peak.
    - level of sky background.
    For each pixel pair, the deviation to the functional fix is evaluated and squared, this deviation is added together with a weighing according to Poisson noise of the data.
    Specified by:
    
    evaluateWithNan in interface Multidimensional
  - evaluate
```
private double evaluate(VectorG fit,
                        boolean print)
```
    Evaluates the functional fit. The vector passed over must have a dimensionality of nine and must provide the data in the following form, ordered by index number.
    - Intesity maximum of the brighter peak
    - pixel-x of intensity maximum.
    - pixel-y of intensity maximum.
    - sigma of intensity in pixel
    - relative intensity of secondary peak
    - delta-x of secondary peak
    - delta-y of secondary peak
    - relative scaling of fwhm of secondary peak.
    - level of sky background.
    For each pixel pair, the deviation to the functional fix is evaluated and squared, this deviation is added together with a weighing according to Poisson noise of the data.
    Parameters:
    
    print - If true, we print x/y count fit count-fit
  - dimension
```
public int dimension()
```
    Returns 8 for normal fits, 6 for pinhole fits.
    
    Specified by:
    
    dimension in interface Multidimensional
  - gauss
```
private static final double gauss(double i0,
                                  double x,
                                  double y,
                                  double sig)
```
    Calculates a two-dimensional gauss.

Class BeamSplitterFit

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DELTAX

DELTAY

KI

KS

IMIRROR

FWHMMIRROR

counts

weight

sky

hole

deltax

deltay

intensity

sigma

Constructor Detail

BeamSplitterFit

Method Detail

evaluateHole

evaluateWithNan

evaluate

dimension

gauss