Miscellaneous Source Match Utilities

Functions
cpl_error_code	enm_associate_std (cpl_table *objtab, cpl_table *stdtab, const float assoc, const int strict_classification, cpl_table **associated_std)
	Associate image catalogue objects with standards.
cpl_error_code	enm_correct_crpix (const char *wcs_method, const char *catalogue, cpl_table *matched_stds, located_image *limage, cpl_matrix **xy_shift)
	Apply median offsets from matched standards table to image.
cpl_error_code	enm_try_all_associations (cpl_table *objtab, cpl_table *stdtab, const double match_rad, cpl_table **matchtab)
	Match standards with objects by trying all possibilities and selecting best.
cpl_error_code	enm_try_association (const double xstd[], const double ystd[], const cpl_size nstd, const double xobj[], const double yobj[], const cpl_size nobj, const cpl_size is, const cpl_size io, cpl_matrix **distances)
	Method to calculate 'distances' matrix given an object association.

Detailed Description

Function Documentation

enm_associate_std()

cpl_error_code enm_associate_std	(	cpl_table *	objtab,
		cpl_table *	stdtab,
		const float	assoc,
		const int	strict_classification,
		cpl_table **	associated_std
	)

Associate image catalogue objects with standards.

Parameters

objtab	Table of objects in image
stdtab	Table of standards
assoc	Radius of association (pixels)
strict_classification	True to only consider stellar round objects
associated_std	A table containing data for the associated objects

Returns

A CPL error code

The routine matches catalogue objects with standards that lie within 'assoc' pixels. If either image or standard catalogue is NULL then the routine returns immediately with no error and without modifying associated_std.

Definition at line 72 of file eris_nix_match.c.

enm_correct_crpix()

cpl_error_code enm_correct_crpix	(	const char *	wcs_method,
		const char *	catalogue,
		cpl_table *	matched_stds,
		located_image *	limage,
		cpl_matrix **	xy_shift
	)

Apply median offsets from matched standards table to image.

Parameters

wcs_method	String describing the correction method
catalogue	Name of reference catalogue
matched_stds	Table of matched standards
limage	The image to be corrected
xy_shift	Matrix containing corrections applied

Returns

A CPL error code

The routine calculates the median shifts in x and y implicit in the coordinates in the matched_stds table. These shifts are applied to the CRPIX1 and CRPIX2 keywords in the image to line up the object and standard positions.

Definition at line 278 of file eris_nix_match.c.

Referenced by enu_correct_wcs().

enm_try_all_associations()

cpl_error_code enm_try_all_associations	(	cpl_table *	objtab,
		cpl_table *	stdtab,
		const double	match_rad,
		cpl_table **	matchtab
	)

Match standards with objects by trying all possibilities and selecting best.

Parameters

objtab	Table of objects in image.
stdtab	Table of standards to pattern match.
match_rad	Max distance between matching obj and std (pixels).
matchtab	Pointer to table with matched standard/object pairs.

Returns

A CPL error code

An object table from hdrl_catalogue and a standard star table, from either casu_getstds or hdrl_catalogue, are given.

All possible associations between standards and objects are tried and a metric of the pattern match is calculated for each - that is, the number of std/obj pairs that lie within 'match_rad' pixels of each other.

The association with the highest metric is selected, and a table is constructed of the std/obj matches found for it.

Definition at line 400 of file eris_nix_match.c.

References enm_try_association().

Referenced by enu_correct_wcs().

enm_try_association()

cpl_error_code enm_try_association	(	const double	xstd[],
		const double	ystd[],
		const cpl_size	nstd,
		const double	xobj[],
		const double	yobj[],
		const cpl_size	nobj,
		const cpl_size	is,
		const cpl_size	io,
		cpl_matrix **	distances
	)

Method to calculate 'distances' matrix given an object association.

Parameters

xstd	Array containing x-coords of standards
ystd	Array containing y-coords of standards
nstd	Number of standards
xobj	Array containing x-coords of objects
yobj	Array containing y-coords of objects
nobj	Number of objects
is	Index of match standard
io	Index of match object
distances	out cpl_matrix containing the resulting distances between matched stds/objs

Returns

Matrix containing the resulting distances between matched stds/objs

Arrays with x,y coords of standards and objects are given, and a specification of which standard and which object are to be matched. The routine calculates the implied offset between standards and objects, and shifts the objects by this amount to now be in the 'standard' frame. A matrix is populated with the distances between each standard and each object, and returned.

Definition at line 677 of file eris_nix_match.c.

Referenced by enm_try_all_associations().