programme to find emission lines in spectra More...

#include <sc_specdiss.h>

cpl_error_code	sc_specdiss_find_emissionlines (cpl_table input_spectrum, cpl_table linetab, cpl_parameterlist parlist, const cpl_table groups)

cpl_error_code	sc_specdiss_find_isolatedlines (cpl_table linetab, cpl_table input_spectrum, cpl_parameterlist *parlist)

cpl_error_code	sc_specdiss_find_localmaxima (cpl_table input_table, char newcolname, char *colname, const double lower_threshold, const double upper_threshold)

cpl_error_code	sc_specdiss_find_valuesoutside (cpl_table input_table, char newcolname, char *colname, const double lowlim, const double uplim)

int	sc_specdiss_count_lines (const cpl_table *intable)

cpl_error_code	sc_specdiss_create_hist (cpl_table hist, const cpl_table input_table, char *col_name, const int n_bins)

void	sc_specdiss_init_linetab (cpl_table *linetab)

cpl_error_code	sc_specdiss_merge_speclinelist (cpl_table spec, const cpl_table groups, const cpl_parameterlist *parlist)

cpl_error_code	sc_specdiss_identify_airglowlines (cpl_table *spec)

cpl_error_code	sc_specdiss_find_valuesabove (cpl_table input_table, char newcolname, char *colname, const double lowlim)

Detailed Description

programme to find emission lines in spectra

Author: Wolfgang Kausch, Stefan Noll, & ESO In-Kind Team Innsbruck

Since: 01 Feb 2011

Date: 17 Sep 2013

Definition in file sc_specdiss.c.

Function Documentation

◆ sc_specdiss_count_lines()

int sc_specdiss_count_lines ( const cpl_table * intable )

Routine to count detected line peaks, i.e. counting the # of rows flagged with a value > 0 in column "peaks" of intable

INPUT:

Parameters

intable input CPL table

OUTPUT:

Returns: number of detected line peaks

Definition at line 866 of file sc_specdiss.c.

◆ sc_specdiss_create_hist()

cpl_error_code sc_specdiss_create_hist	(	cpl_table *	hist,
		const cpl_table *	input_table,
		char *	col_name,
		const int	n_bins
	)

Routine to create a histogram binning with n_bins from a choosable column of an input CPL table. The histogram data is stored into a CPL table

INPUT:

Parameters

hist	CPL table to be filled with histogram information
input_table	table containing column "col_name"
col_name	column of input table to be used for binning
n_bins	# of histogram bins

OUTPUT:

Parameters

hist	CPL table with histogram information (bins/counts)

ERRORS:

CPL_ERROR_NONE: no error occurred

Definition at line 894 of file sc_specdiss.c.

◆ sc_specdiss_find_emissionlines()

cpl_error_code sc_specdiss_find_emissionlines	(	cpl_table *	input_spectrum,
		cpl_table *	linetab,
		cpl_parameterlist *	parlist,
		const cpl_table *	groups
	)

This routine is aimed to detect line peaks in an input spectrum to separate pixels belonging to lines and to the continuum. The lines are finally separated in isolated/blended lines, the first being used to determine a rough estimate of the FWHM of the spectrum.

The input spectrum has to be a CPL table containing (at least) the following columns:

 col #1: lambda
 col #2: flux

The wavelength dimension must be [micron], the flux is arbitrary. An additional column labelled "class" is added to the spectrum table, which is used to classify the single pixels in the following way:

 0 = Continuum
 1 = Line pixel
 2 = Line peak
 3 = Isolated line peak

The second input parameter must be an empty CPL table, but already initialised with sc_specdiss_init_linetab(). This table is filled with information about the detected lines (see sc_specdiss_find_isolatedlines).

INPUT:

Parameters

input_spectrum	table containing input spectra
linetab	empty table to be filled with line information
parlist	CPL parameter list containing information of the parameter file
groups	CPL table with airglow line information

OUTPUT:

ERRORS:

CPL_ERROR_NONE: no error occurred
CPL_ERROR_ILLEGAL_INPUT: missing column "lambda" or "flux" in input spectrum, zero length input spectrum

Definition at line 59 of file sc_specdiss.c.

References SC_MAXLEN, sc_specdiss_find_isolatedlines(), sc_specdiss_find_localmaxima(), sc_specdiss_identify_airglowlines(), sc_specdiss_merge_speclinelist(), and SC_THERMIRLIM.

Referenced by sc_skycorr_subcont().

◆ sc_specdiss_find_isolatedlines()

cpl_error_code sc_specdiss_find_isolatedlines	(	cpl_table *	linetab,
		cpl_table *	input_spectrum,
		cpl_parameterlist *	parlist
	)

This programme searches for isolated lines (required for determining the FWHM) in an input spectrum.

The following two criteria to identify an isolated line are applied:

 (1) Distance to neighbouring line: larger / equal
         [min_line_dist_fac] * [measured FWHM] (in px);
     For first line: = distance to spectrum start (in px),
         last  line: = distance to spec end
 (2) Symmetry of line shape: # pixels left of peak = # pixels on
     the right hand side (+/- 1 px)

The input spectrum must be a CPL table containing (at least) the following columns:

 col #1: lambda
 col #2: flux
 col #3: class

The column "class" finally contains information on the pixel type in following way:

 0 = Continuum
 1 = Line pixel
 2 = Line peak
 3 = Isolated line peak (used for FWHM determination)

Additionally, the CPL table linetab is filled with the following information:

 col #1:  width          - line width [pixels]
 col #2:  peak_loc       - Peak location [pixels]
 col #3:  peak_lam       - Peak location [wavelength]
 col #4:  peak_flux      - Flux of line peak pixel
 col #5:  px_bef         - number of line pixels before line peak
 col #6:  px_aft         - number of line pixels after line peak
 col #7:  line_px_start  - first pixel of line
 col #8:  line_px_end    - last pixel of line
 col #9:  dist_bef       - distance to previous line [pixel]
 col #10: dist_aft       - distance to subsequent line [pixels]
 col #11: isol_flag      - flag indicating an isol. line
                           (0=no / 1=yes)
 col #12: fwhm           - Full Width Half Maximum column (to be
                           filled later)
 col #13: line_list      - Line list value:
                                 =0 : not present
                                 >0 : # of linelist lines in pixel

Note: In the case of a wavelength-dependent line width (varfwhm = 1), the measured fwhm and peak_flux are modified in the way as the line would be moved to the centre of the wavelength range of the input spectrum.

INPUT:

Parameters

linetab	table to be filled with information on the lines
input_spectrum	table containing input spectra
parlist	CPL parameter list containing information of the parameter file

OUTPUT:

Parameters

linetab	information about the detected lines is stored to this table
input_spectrum	spectrum table col "class" is filled

ERRORS:

CPL_ERROR_NONE: no error occurred

Definition at line 346 of file sc_specdiss.c.

Referenced by sc_specdiss_find_emissionlines().

◆ sc_specdiss_find_localmaxima()

cpl_error_code sc_specdiss_find_localmaxima	(	cpl_table *	input_table,
		char *	newcolname,
		char *	colname,
		const double	lower_threshold,
		const double	upper_threshold
	)

Routine to search for local maxima below and above two thresholds within a column table. It is used to identify line peaks within a range of pixels belonging to a single line.

INPUT:

Parameters

input_table	table containing input spectra
newcolname	table column to be added to input_table
colname	name of column to be used for search
lower_threshold	lower threshold for search
upper_threshold	upper threshold for search

OUTPUT:

Parameters

input_table	an additional column is added to the input table
newcolname	table column to be added to input_table containing search results

ERRORS:

CPL_ERROR_NONE: no error occurred

Definition at line 634 of file sc_specdiss.c.

References SC_MAXLEN, sc_specdiss_find_valuesoutside(), and SC_THERMIRLIM.

Referenced by sc_specdiss_find_emissionlines().

◆ sc_specdiss_find_valuesabove()

cpl_error_code sc_specdiss_find_valuesabove	(	cpl_table *	input_table,
		char *	newcolname,
		char *	colname,
		const double	lowlim
	)

Routine to search for values within a column table: lowlim <= VALUES

An additional column (2nd input parameter) is added to the input table, rows fulfilling the condition are flagged (value=1, =0 otherwise).

INPUT:

Parameters

input_table	table containing input spectra
newcolname	column to be added to input table containing search results
lowlim	lower threshold
colname	column to be used for search

OUTPUT:

Parameters

input_table	an additional column is added to the input table
newcolname	table column to be added to input_table containing search results

ERRORS:

CPL_ERROR_NONE: no error occurred

Definition at line 1234 of file sc_specdiss.c.

◆ sc_specdiss_find_valuesoutside()

cpl_error_code sc_specdiss_find_valuesoutside	(	cpl_table *	input_table,
		char *	newcolname,
		char *	colname,
		const double	lowlim,
		const double	uplim
	)

Routine to search for entries in a table column fulfilling the following criteria:

 entry <= lowlim && entry >= uplim

An additional column (2nd input parameter) is added to the input table, rows fulfilling the condition are flagged:

 value = -1,  if entry <= lowlim
 value =  1,  if entry >= uplim
 value =  0,  otherwise

INPUT:

Parameters

input_table	table containing input spectra
newcolname	column to be added to input table containing search results
lowlim	lower threshold
uplim	upper threshold
colname	column to be used for search

OUTPUT:

Parameters

input_table	an additional column is added to the input table
newcolname	table column to be added to input_table containing search results

ERRORS:

CPL_ERROR_NONE: no error occurred

Definition at line 802 of file sc_specdiss.c.

Referenced by sc_specdiss_find_localmaxima().

◆ sc_specdiss_identify_airglowlines()

cpl_error_code sc_specdiss_identify_airglowlines ( cpl_table * spec )

Identifies airglow lines in spectrum and updates 'linelist' column

INPUT:

Parameters

spec	CPL table with spectrum

OUTPUT:

Parameters

spec	spectrum table with updated 'linelist' column

Definition at line 1202 of file sc_specdiss.c.

Referenced by sc_specdiss_find_emissionlines().

◆ sc_specdiss_init_linetab()

void sc_specdiss_init_linetab ( cpl_table * linetab )

Routine to initialise CPL table containing all information about the detected lines. The following columns are added:

 col #1:  width          - line width [pixels]
 col #2:  peak_loc       - Peak location [pixels]
 col #3:  peak_lam       - Peak location [wavelength]
 col #4:  peak_flux      - Flux of line peak pixel
 col #5:  px_bef         - number of line pixels before line peak
 col #6:  px_aft         - number of line pixels after line peak
 col #7:  line_px_start  - first pixel of line
 col #8:  line_px_end    - last pixel of line
 col #9:  dist_bef       - distance to previous line [pixel]
 col #10: dist_aft       - distance to subsequent line [pixels]
 col #11: isol_flag      - flag indicating an isol. line
                           (0=no / 1=yes)
 col #12: fwhm           - Full Width Half Maximum column
 col #13: line_list      - Line list value:
                                 =0 : not present
                                 >0 : # of linelist lines in pixel

INPUT:

Parameters

linetab empty CPL table

OUTPUT:

Parameters

linetab table with initialised columns for information on detected lines

Definition at line 974 of file sc_specdiss.c.

Referenced by sc_skycorr().

◆ sc_specdiss_merge_speclinelist()

cpl_error_code sc_specdiss_merge_speclinelist	(	cpl_table *	spec,
		const cpl_table *	groups,
		const cpl_parameterlist *	parlist
	)

Routine to read line list and merge line list with input spectrum. The line list is read from a file, all lines of the list are marked in the column "linelist" of the input spectrum table in the following way:

 1 = line list pixel
 2 = line list peak

INPUT:

Parameters

spec	CPL table with input spectrum
groups	CPL table with airglow line information
parlist	parameter list containing file name of line list

OUTPUT:

Parameters

spec	CPL table with initialised columns for information on detected lines

Definition at line 1023 of file sc_specdiss.c.

Referenced by sc_specdiss_find_emissionlines().