EllipticalSource¶

class sofia_redux.scan.source_models.beams.elliptical_source.EllipticalSource(peak=1.0, x_mean=0.0, y_mean=0.0, x_fwhm=0.0, y_fwhm=0.0, theta=<Quantity 0. deg>, peak_unit=None, position_unit=None, gaussian_model=None)[source]¶

Bases: GaussianSource

Initialize an EllipticalSource model.

The elliptical source is used to represent a Gaussian source using elliptical parameters such as major/minor FWHM, elongation and rotation.

Parameters:

peakfloat or units.Quantity, optional: The peak amplitude of the Gaussian.
x_meanfloat or units.Quantity, optional: The position of the peak along the x-axis.
y_meanfloat or units.Quantity, optional: The position of the peak along the y-axis.
x_fwhmfloat or units.Quantity, optional: The Full-Width-Half-Max beam width in the x-direction.
y_fwhmfloat or units.Quantity, optional: The Full-Width-Half-Max beam width in the y-direction.
thetafloat or units.Quantity, optional: The rotation of the beam pertaining to x_fwhm and y_fwhm in relation to the actual (x, y) coordinate axis. If a float value is supplied, it is assumed to be in degrees.
peak_unitunits.Unit or units.Quantity or str, optional: The physical units for the peak amplitude. The default is dimensionless.
position_unitunits.Unit or units.Quantity or str, optional: The physical units of all position based parameters (x_mean, y_mean, x_fwhm, y_fwhm)
gaussian_modelGaussian2D, optional: If supplied, extracts all the above parameters from the supplied model.

Attributes Summary

`angle`	Return the angle of the ellipse.
`angle_rms`	Return the rms of the angle.
`elongation_rms`	Return the RMS of the elongation.
`major_fwhm`	Return the major FWHM of the Gaussian ellipse.
`major_fwhm_rms`	Return the major FWHM RMS.
`major_fwhm_weight`	Return the major FWHM weight (1/variance) of the Gaussian ellipse.
`minor_fwhm`	Return the minor FWHM of the Gaussian ellipse.
`minor_fwhm_rms`	Return the minor FWHM RMS.
`minor_fwhm_weight`	Return the minor FWHM weight (1/variance) of the Gaussian ellipse.

Methods Summary

`edit_header`(header[, fits_id, beam_name, ...])	Edit a FITS header with the elliptical beam parameters.
`find_source_extent`(image[, max_iterations, ...])	Find the extent of the source and shape.
`fit_map_least_squares`(map2d[, degree, ...])	Fit the Gaussian to a given map using LSQ method (adaptTo).
`get_data`(map2d[, size_unit])	Return a dictionary of properties for to the source model on a map.
`measure_shape`(image[, min_radius_scale, ...])	Measure the shape of an elliptical source on an image.
`pointing_info`(map2d)	Return a list of strings with pointing information.
`set_elongation`([major, minor, weight, angle])	Set the elongation parameter.

Attributes Documentation

angle¶

Return the angle of the ellipse.

Returns:

angleunits.Quantity

angle_rms¶

Return the rms of the angle.

Returns:

angle_rmsunits.Quantity

elongation_rms¶

Return the RMS of the elongation.

Returns:

elongation_rmsfloat

major_fwhm¶

Return the major FWHM of the Gaussian ellipse.

Returns:

majorunits.Quantity

major_fwhm_rms¶

Return the major FWHM RMS.

Returns:

major_rmsfloat or units.Quantity

major_fwhm_weight¶

Return the major FWHM weight (1/variance) of the Gaussian ellipse.

Returns:

major_weightfloat or units.Quantity

minor_fwhm¶

Return the minor FWHM of the Gaussian ellipse.

Returns:

minorunits.Quantity

minor_fwhm_rms¶

Return the minor FWHM RMS.

Returns:

minor_rmsfloat or units.Quantity

minor_fwhm_weight¶

Return the minor FWHM weight (1/variance) of the Gaussian ellipse.

Returns:

minor_weightfloat or units.Quantity

Methods Documentation

edit_header(header, fits_id='', beam_name=None, size_unit=None)[source]¶

Edit a FITS header with the elliptical beam parameters.

Parameters:

headerastropy.io.fits.header.Header: The FITS header to edit.
fits_idstr, optional: Not used.
beam_namestr, optional: The name of the beam.
size_unitastropy.units.Unit or Quantity or str, optional: If set, convert the major/minor beam values to this unit before setting in the header.

Returns:

None

find_source_extent(image, max_iterations=40, radius_increment=1.1, tolerance=0.05)[source]¶

Find the extent of the source and shape.

Parameters:

imageFlaggedArray
max_iterationsint, optional: The maximum number of iterations, each of which increases the search radius by radius_increment.
radius_incrementfloat, optional: The factor by which to increase the search radius between iterations.
tolerancefloat, optional: Halt iterations if the change in data sum is less than 1 + tolerance between iterations.

Returns:

None

fit_map_least_squares(map2d, degree=3, reduce_degrees=False)[source]¶

Fit the Gaussian to a given map using LSQ method (adaptTo).

Parameters:

map2dMap2D or Observation2D
degreeint, optional: The spline degree used to fir the map peak value.
reduce_degreesbool, optional: If True, allow the spline fit to reduce the number of degrees in cases where there are not enough points available to perform the spline fit of degree. If False, a ValueError will be raised if such a fit fails.

Returns:

data_sumfloat: The sum of the source withing the source radius.

get_data(map2d, size_unit=None)[source]¶

Return a dictionary of properties for to the source model on a map.

The key values returned are:

peak: The fitted peak value

dpeak: The fitted peak value RMS

peakS2N: The peak signal-to-noise ratio

int: The integral of the peak on the map

dint: The integral rms of the peak on the map

intS2N: The significance of the peak on the map

FWHM: The full-width-half maximum of the peak

dFWHM: The full-width-half-maximum RMS of the peak

a: The major FWHM

b: The minor FWHM

da: The major FWHM RMS

db: The minor FWHM RMS

angle: The rotation of the major axis

dangle: The RMS of the rotation of the major axis

Parameters:

map2dMap2D: The map for which to calculate an integral.
size_unitunits.Unit or str, optional: If set, converts FWHM and dFWHM to size_unit.

Returns:

dict

measure_shape(image, min_radius_scale=0.0, max_radius_scale=1.5)[source]¶

Measure the shape of an elliptical source on an image.

Parameters:

imageFlaggedArray
min_radius_scalefloat, optional
max_radius_scalefloat, optional

Returns:

None

pointing_info(map2d)[source]¶

Return a list of strings with pointing information.

Parameters:

map2dMap2d

Returns:

list (str)

set_elongation(major=None, minor=None, weight=inf, angle=None)[source]¶

Set the elongation parameter.

Parameters:

majorfloat or astropy.units.Quantity, optional: The major axis of the ellipse. If not supplied defaults to the fwhm of the Gaussian in the x-direction.
minorfloat or astropy.units.Quantity, optional: The minor axis of the ellipse. If not supplied defaults to the fwhm of the Gaussian in the y-direction.
weightfloat or astropy.units.Quantity, optional: The weight (inverse variance) of the elongation. If not supplied defaults to infinity (exact).
anglefloat or astropy.units.Quantity, optional: The angle of the principle axis. If not supplied defaults to the position angle of the Gaussian. If a float value is supplied, is assumed to be in radians.

Returns:

None

Navigation

EllipticalSource¶