Wavelength calibration routines

Functions
cpl_polynomial *	sofi_wavelength_engine (const cpl_image *in, const char *table_name, const char *oh, const char *xe, const char *ne, const cpl_polynomial *phdisprel, double slit_width, int degree, double wl_err, int nsamples, int use_ppm, int plot, double *xcorr)
	Compute a dispersion relation.
double	sofi_get_slitwidth (const char *filename)
	Find out the slit width.
cpl_polynomial *	sofi_get_disprel_estimate (const char *filename, int poly_deg)
	Estimate the instrument dispersion relation.

Detailed Description

Function Documentation

sofi_get_disprel_estimate()

cpl_polynomial * sofi_get_disprel_estimate	(	const char *	filename,
		int	poly_deg )

Estimate the instrument dispersion relation.

Parameters

filename	input file name
poly_deg	polynomial degree

Returns

1 newly allocated cpl_polynomial or NULL on error

Definition at line 313 of file sofi_wavelength.c.

References sofi_pfits_get_mode(), and sofi_pfits_get_naxis2().

sofi_get_slitwidth()

double sofi_get_slitwidth

(

const char *

filename

)

Find out the slit width.

Parameters

filename

SOFI fits file name

Returns

the slit width in pixels or -1 in error case

Definition at line 263 of file sofi_wavelength.c.

References sofi_pfits_get_opti1_id(), and sofi_pfits_get_pixscale().

sofi_wavelength_engine()

cpl_polynomial * sofi_wavelength_engine	(	const cpl_image *	in,
		const char *	table_name,
		const char *	oh,
		const char *	xe,
		const char *	ne,
		const cpl_polynomial *	phdisprel,
		double	slit_width,
		int	degree,
		double	wl_err,
		int	nsamples,
		int	use_ppm,
		int	plot,
		double *	xcorr )

Compute a dispersion relation.

Parameters

in	Allocated spectroscopic image
table_name	Spectral table name (see below)
oh	the oh lines catalog
xe	the xe lines catalog
ne	the ne lines catalog
phdisprel	first guess polynomial (phys. mod.?)
slit_width	Width in pixels of the slit used
degree	Degree of the polynomial to fit the matched lines
wl_err	the wl error
nsamples	Number of samples for wavelength computation
use_ppm	Use the point pattern matching at the end
plot	Flag for plots
xcorr	the cross correlation factor (computed)

Returns

The polynomial with th solution or NULL in error case

Compute a dispersion relation from a spectroscopic image showing some strong emission lines. A vital assumption is that strong emission lines can be seen in the image. The removal of thermal background will attempt to remove from the spectroscopic image any low-frequency components, i.e. any features that are a lot wider than the slit width.

The spectral table name is a character string. Possible values are:

"oh" : OH lines "Xe" : Xenon lines "Ar" : Argon lines "Xe+Ar" : Xenon and Argon lines

Definition at line 150 of file sofi_wavelength.c.