stella.adapter
Class ModelShift.PinholeModel

java.lang.Object
  stella.adapter.ModelShift.PinholeModel

All Implemented Interfaces:

DataModel, GradientModel

Enclosing class:

ModelShift

public static class ModelShift.PinholeModel
extends Object
implements GradientModel

A pinhole model is the model of a star with fitted intensity and FWHM close to the fixed pinhole position at the given coordinates. We fit four parameters, the Δx and Δy of the relative star shift, the total flux of the star and the FWHM of the star.

Field Summary

private double	beta The beta of the moffat function.
private double[]	data The array of the measured data points minus background.
private Dimension	geometry The geometry of the frame.
private VectorG	m0 A first estimate of the model parameters.
private double[]	photsig The estimated photon noise sigma.
private double	pindip For modeling the pinhole.
private Point2D	pinhole The fixed pinhole position.
private double	pinsize The pinhole size in pixel.
private double	pinsteep For modeling the pinhole, the steepness.

Constructor Summary

private

ModelShift.PinholeModel(nom.tam.fits.ImageHDU measured, Rectangle box, double back, double backerr, Point2D pos, double size, double k, double deep, double moffat) Constructs a new data model for the pinhole.

Method Summary

double	evaluateModel(VectorG dxdy, VectorG xy) Per definition, the independant variable, time, is here a two-dimensional vector specifying the location of the pixel.
protected VectorG	getFirstModel() Returns a first estimate.
Matrix	getGradientMatrix(VectorG dxdy) Returns the gradient matrix.
int	getMeasureCount() Return the number of measurements in the data model.
double[]	getMeasurementErrors() Returns the photon noise.
double[]	getMeasures() Returns the data array.
double[]	getModel(VectorG dxdy) Per definition, the model data is a Vector of all data points, not an area.
int	getParameterCount() The model parameters are Shift of star to pinhole in x-direction, pixel Shift of star to pinhole in y-direction, pixel Total ADU flux of star FWHM of star in pixel. This we
double[]	getResiduals(VectorG a) Returns the residulas.
VectorG[]	getTimes() Returns the evaluation points.
double[]	getTotalErrors() Returns the photon noise.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

pinhole

private Point2D pinhole

The fixed pinhole position.

pinsize

private double pinsize

The pinhole size in pixel.

pinsteep

private double pinsteep

For modeling the pinhole, the steepness.

pindip

private double pindip

For modeling the pinhole.

beta

private double beta

The beta of the moffat function.

geometry

private Dimension geometry

The geometry of the frame.

data

private double[] data

The array of the measured data points minus background.

photsig

private double[] photsig

The estimated photon noise sigma.

m0

private VectorG m0

A first estimate of the model parameters.

Constructor Detail

ModelShift.PinholeModel

private ModelShift.PinholeModel(nom.tam.fits.ImageHDU measured,
                                Rectangle box,
                                double back,
                                double backerr,
                                Point2D pos,
                                double size,
                                double k,
                                double deep,
                                double moffat)
                         throws IOException,
                                nom.tam.fits.FitsException

Constructs a new data model for the pinhole. The model is constructed with the measured data (plus the applicable box) and the measured backgound noise. The modeling parameters for the pinhole and the beta of the stellar Moffat function are also stated.

Throws:

IOException

nom.tam.fits.FitsException

Method Detail

getParameterCount

public int getParameterCount()

The model parameters are

• Shift of star to pinhole in x-direction, pixel
• Shift of star to pinhole in y-direction, pixel
• Total ADU flux of star
• FWHM of star in pixel.

This we

Specified by:

getParameterCount in interface DataModel

Returns:

4.

getMeasureCount

public int getMeasureCount()

Return the number of measurements in the data model. This is the number of pixel in the image.

Specified by:

getMeasureCount in interface DataModel

Returns:

The number of measurements in the data model. This equals the dimension of the return vector in DataModel.getModel(vec_math.VectorG).

getMeasures

public double[] getMeasures()

Returns the data array.

Specified by:

getMeasures in interface DataModel

getTotalErrors

public double[] getTotalErrors()

Returns the photon noise.

Specified by:

getTotalErrors in interface DataModel

getResiduals

public double[] getResiduals(VectorG a)

Returns the residulas.

Specified by:

getResiduals in interface DataModel

Parameters:

a - The model parameters, not necessarily the best fit.

getMeasurementErrors

public double[] getMeasurementErrors()

Returns the photon noise.

Specified by:

getMeasurementErrors in interface DataModel

getTimes

public VectorG[] getTimes()

Returns the evaluation points. This is an array of geometry.width*geometry.height length, each entry is a Vector2D with pixel coordinates sampling the entire effective area. The name is missleading, though.

Specified by:

getTimes in interface DataModel

Returns:

An array of dimension DataModel.getMeasureCount().

getFirstModel

protected VectorG getFirstModel()

Returns a first estimate.

getModel

public double[] getModel(VectorG dxdy)

Per definition, the model data is a Vector of all data points, not an area. The model parameters are

• Shift of star to pinhole in x-direction, pixel
• Shift of star to pinhole in y-direction, pixel
• Total ADU flux of star
• FWHM of star in pixel.

Specified by:

getModel in interface DataModel

Parameters:

dxdy - The model parameters

Returns:

A model for the data points depending on the model parameters.

evaluateModel

public double evaluateModel(VectorG dxdy,
                            VectorG xy)

Per definition, the independant variable, time, is here a two-dimensional vector specifying the location of the pixel. It can be non-integer. The model parameters are

• Shift of star to pinhole in x-direction, pixel
• Shift of star to pinhole in y-direction, pixel
• Total ADU flux of star
• FWHM of star in pixel.

Specified by:

evaluateModel in interface DataModel

Parameters:

dxdy - The model parameters as defined above

The - pixel location as a two-dim vector.

getGradientMatrix

public Matrix getGradientMatrix(VectorG dxdy)

Returns the gradient matrix. Only the stellar model via the Moffat function depends on the model parameters.

Specified by:

getGradientMatrix in interface GradientModel