astrowisp.utils.explore_prf module

Class Inheritance Diagram

Create some plots helpful for picking PSF grid.

class astrowisp.utils.explore_prf.AlglibSpline(prf_data, resolution, penalty, domain)

Bases: object

Wrap alglib based splines so they can be evaluated on scipy arrays.

__call__(x, y)

Evaluate the spline.

__init__(prf_data, resolution, penalty, domain)

Fit the spline on the given data.

Parameters:

• prf_data – The return value of get_prf_data().

• resolution (int, int) – The grid resolution to use when building the spline.

• penalty (float) – The nonlinearity penalty when fitting the spline.

• domain (float, float, float, float) – The area (xmin, xmax, ymin, ymax) over which the spline will be derived.

Returns:

None

plot_grid_boundaries(direction, color)

Add vertical lines to the current axis showing the grid along direction.

Parameters:

direction (str) – Either ‘x’, or ‘y’, selecting which direction to show the grid lines along.

Returns:

None

astrowisp.utils.explore_prf.extract_pixel_data(cmdline_args, image_slices, sources=None)

Get the pixel level data from the input image required for the plot.

Parameters:

• cmdline_args – The parsed command line arguments.

• image_slices – How to split the image when plotting (the return value of get_image_slices()).

• sources (scipy.array or None) – If not None, it should be an array with equivalent structure to get_source_info(). If None, get_source_info() is used to initialize it.

Returns:

A list of the PRF data (see return of get_prf_data()) for each image slice each entry contains the data and a plot label.

Return type:

List

astrowisp.utils.explore_prf.find_pixel_offsets(sources, prf_range, image_resolution, crowding_distance, plot=False)

Return the positions of pixels within prf range relative to source centers.

Parameters:

• sources – The return value of get_source_info().

• prf_range – See –prf-range command line argument.

• image_resolution (int, int) – The x and y resolution of the image under investigation.

• crowding_distance (float) – The minimum distance between a source and its closest neighbor to still consider the source isolated.

• plot (bool) – If True, show plots of the offsets and norm images.

Returns:

• x_off: The field giving the offset of the pixel center from the source position in the x direction

• y_off: The field giving the offset of the pixel center from the source position in the y direction

• norm: The normalization to use for the pixel response.

Pixels that are not within range of any PSF or that are within more than one PSF’s range have nan entries.

Return type:

2-D field array

astrowisp.utils.explore_prf.fit_spline(prf_data, domain, cmdline_args)

Return the best-fit spline to the PRF per the command line config.

astrowisp.utils.explore_prf.get_image_slices(splits, inner_only)

Return [(x-slice, y-slice, x_index, y_index), …] per –split-image arg.

Parameters:

• splits – The parsed image splits directly from the command line.

• inner_only (bool) – If True, slices in contact with the outer border of the image are discarded.

Returns:

Array slices directly useable to index the image implementing the splitting specified on the command line.

Return type:

[(x-slice, y-slice, x_index, y_index), …]

astrowisp.utils.explore_prf.get_plot_tasks(cmdline_args)

Generator for all the plots that must be created.

Parameters:

cmdline_args – The parse command line configuration.

Yields:

dict – The parsed PRF slice directly taken from the command line to plot

[(str on None), …]: List of the filenames to save the plot if each

slice is saved separately. Appropriate length of Nones otherwise.

str or None: The filanem to save a combined plot of all pieces of the

image together or None if individual images are saved separately.

astrowisp.utils.explore_prf.get_prf_data(pixel_values, pixel_stddev, pixel_offsets, error_threshold=0.1)

Return the PRF measurements for (a subset of) the image.

Parameters:

• pixel_values (2-D float array) – The calibrated pixel responses from the image to include in the plot.

• pixel_stddev (2-D float array) – The estimated standard deviation of pixel_values.

• pixel_offsets – The slice of the return value of find_pixel_offsets() corresponding to pixel_values.

• error_threshold (float) – See –error-threshold command line argument

Returns:

• The x-offsets of the points at which PRF measurements are available.

• The y-offsets of the points at which PRF measurements are available.

• The measured normalized PRF at the available offsets

• estimated errors of the PRF measurements.

Return type:

(2-D float array, 2-D float array, 2-D float array, 2-D float array)

astrowisp.utils.explore_prf.get_source_info(*, pixel_array, stddev_array, mask_array, source_positions, aperture, bg_radii)

Return field array containing source positions, fluxes and backgrounds.

Parameters:

• pixel_array (2-D array like) – The measured values of the image pixels.

• stddev_array (2-D array like) – The estimated variance of the image pixels.

• mask_array (2-D array like) – Quality flags for the image pixels.

• source_positions – The return value from get_source_positions().

• aperture – The size of the aperture to use for measuring the flux.

• bg_radii ((float, float)) – The inner and outer radius to use for the background annulus.

Returns:

All relevant source information in the following fields:

• x: The x coordinates of the sources.

• y: The y coordinates of the sources.

• flux: The measured fluxes of the sources.

• flux_err: Estimated error of the flux.

• bg: The measured backgrounds of the sources.

• bg_err: Estimated error of the background.

• bg_npix: The number of pixels used in determining the background.

Return type:

(scipy field array)

astrowisp.utils.explore_prf.get_source_positions(catalogue_fname, trans_fname, image_resolution)

Return [(x, y), …] positions of the sources in the image.

Parameters:

• catalogue_fname (str) – The filename of a catalogue query containing all sources in the image (could contain more).

• trans_fname (str) – The filename of the grtrans file for transforming tan-projected (xi, eta) to image positions.

• image_resolution ((x_res, y_res)) – The resolution of the input image. Used to determine which sources project outside the image.

Returns:

A list of the (x, y) positions of the sources in the image.

Return type:

[(float, float), …]

astrowisp.utils.explore_prf.get_trans_fname(frame_fname, trans_pattern)

Return the filename of the trans file corresponding to a given frame.

Parameters:

• frame_fname (str) – The filename of the FITS frame used for plotting.

• trans_pattern (str) – The pattern for the filename of the transformation file specified on the command line.

Returns:

The filename of the transformation file.

Return type:

str

astrowisp.utils.explore_prf.list_plot_filenames(cmdline_args)

List the filenames of all the plots that will be generated.

astrowisp.utils.explore_prf.main(cmdline_args)

Avoid polluting global namespace.

astrowisp.utils.explore_prf.pad_prf_data(prf_data, cmdline_args)

Return PRF data zero-padded for fitting and the spline fit domain.

astrowisp.utils.explore_prf.parse_command_line(parser=None, assume_sources=False, add_config_file=True, add_frame_arg=True)

Return the command line arguments as attributes of an object.

Parameters:

parser (ArgumentParser) – If not None, should be a valid command line parser to which further arguments are addded by this method.

Returns:

See ArgumentParser.parse_args().

astrowisp.utils.explore_prf.plot_3d_prf(cmdline_args, meshgrid_x, meshgrid_y, prf_slice_splines)

Plot a 3D slice of the PRF.

Parameters:

• cmdline_args – The parse command line configuration.

• meshgrid_x – The meshgrid generated for evaluating the PRF made from the grid points of the star_shape_grid

• meshgrid_y – The meshgrid generated for evaluating the PRF made from the grid points of the star_shape_grid

• prf_slice_splines – The evaluated PRF at the meshgrid points extracted from slice_splines

Returns:

None

astrowisp.utils.explore_prf.plot_entire_prf(cmdline_args, image_slices, grid_x, grid_y, sources=None)

Plots the entire PRF on a 3d axes and displays it to the user.

Parameters:

• cmdline_args – The parsed command line arguments.

• image_slices – How to split the image when plotting (the return value of get_image_slices())

• grid_x – The PSF x-grid, pulled from star_shape_grid

• grid_y – The PSF y-grid, pulled from star_shape_grid

• sources (scipy.array or None) – If not None, it should be an array with equivalent structure to get_source_info(). If None, get_source_info() is used to initialize it.

Returns:

None

astrowisp.utils.explore_prf.plot_prf_slice(prf_data, spline, *, label, x_offset=None, y_offset=None, thickness=0.1, error_scale=0.1, points_color='k', marker_size=2, **binning)

Plot a slice of the PRF.

Parameters:

• prf_data – The return value of get_prf_data().

• x_offset/y_offset (float) – Plot a slice of constant x or y (determined by the argument name) offset from the source center.

• thickness (float) – Points with x or y within thickness of the specified offset are included in the plot.

• error_scale (float) – See –error-scale command line argument.

• error_threshold (float) – See –error-threshold command line argument.

Returns:

None

astrowisp.utils.explore_prf.show_plots(slice_prf_data, slice_splines, cmdline_args, append=False)

Generate the plots and display them to the user.

Parameters:

• slice_prf_data (iterable) – List of the result of either get_prf_data() or pad_prf_data() for each image slice.

• slice_splines (iterable) – List of best-fit splines to the data for each image slice. Must support evaluation using arrays of x & y positions.

• cmdline_args – The parsed command line arguments.

Returns

None