IFU Geometric Distortion Correction

Functions
cpl_vector *	eris_ifu_dist_calc_centers_profile (const cpl_vector *profile, cpl_boolean lowerCutLevel)
	Detect peak positions from a collapsed profile.
cpl_vector *	eris_ifu_dist_estimate_low_slitlet (const cpl_vector *est_centers)
	Estimate position of missing low slitlet.
cpl_vector *	eris_ifu_dist_calc_centers_fit (const cpl_vector *profile, const cpl_vector *est_centers, cpl_boolean do_fix_cnt)
	Fit Gaussian profiles to refine center positions.
cpl_error_code	eris_ifu_dist_calc_centers_copy (const cpl_vector *fit_centers, int y_index, double y_value, cpl_table **cen_array)
	Copy fitted centers to the output table array.
cpl_table **	eris_ifu_dist_calc_centers (const hdrl_image *fibre_div, const hdrl_image *fibre_on, int productDepth)
	Calculate slitlet centers across the detector.
int	eris_ifu_distortion_get_narcs (int i, cpl_boolean triple_traces, cpl_boolean cut_off_left, cpl_boolean cut_off_right)
	Determine number of arc traces to process for a slitlet.
cpl_polynomial **	eris_ifu_dist_calc_distortion (cpl_table **slit_edges, cpl_table **centers, int productDepth, cpl_boolean cut_off_left, cpl_boolean cut_off_right, cpl_table **minmax_borders, cpl_propertylist ***qc, cpl_propertylist *pl, cpl_frameset *frameset, const cpl_parameterlist *parlist)
	Calculate distortion polynomials for all slitlets.
cpl_polynomial **	eris_ifu_dist_calc_distortion_full (cpl_table **slit_edges, cpl_table **centers, int productDepth, cpl_boolean cut_off_left, cpl_boolean cut_off_right)
	Calculate distortion polynomials (alternative method)
eris_ifu_vector *	eris_ifu_dist_calc_distortion_fitedge (const cpl_table *edge, const char *col_name, const eris_ifu_vector *y, int n_calib, int n_size, int fit_order, int slitlet, cpl_table *dbg_tbl)
	Fit polynomial to single edge as function of Y.
cpl_error_code	eris_ifu_dist_calc_distortion_fillgrid (cpl_bivector *grid, const eris_ifu_vector *data, cpl_vector *val_to_fit, double x_pos, int n_size, int arc_cnt)
	Fill grid with distortion mapping data.
cpl_polynomial *	eris_ifu_dist_poly_fit_2d_create (cpl_bivector *xy_pos, const cpl_vector *values, double *msee)
	Create 2D polynomial fit from grid data.
cpl_error_code	eris_ifu_dist_save_distortion (cpl_polynomial **poly2d, const cpl_table *minmax_borders, const char *fn, cpl_frameset *frameset, const cpl_parameterlist *parlist, cpl_propertylist **qc)
	Save distortion polynomials to FITS file.
hdrl_image *	eris_ifu_dist_warp_image_full (const hdrl_image *hdrl_img_in, cpl_polynomial **poly_u, int productDepth)
	Warp full image using distortion polynomials (alternative method)
hdrl_image *	eris_ifu_dist_warp_slitlet (const hdrl_image *imgIn, const cpl_polynomial *poly_u, const cpl_polynomial *poly_v, double l_min, double r_max, int slitletNr)
	Warp single slitlet.
hdrl_image *	eris_ifu_dist_warp_image (const hdrl_image *imgIn, cpl_polynomial **poly_u, const cpl_table *borders)
	Warp full detector image by warping each slitlet.
hdrl_image *	eris_ifu_dist_warp_bpm (const hdrl_image *bpmIn, cpl_polynomial **poly_u, const cpl_table *borders, productDepthType productDepth)
	Warp bad pixel mask using distortion polynomials.
hdrl_imagelist *	eris_ifu_stack_warped (const hdrl_image *imgIn, const int *rowIx)
	Stack warped image into cube format.
cpl_error_code	eris_ifu_dist_warp_stats (const hdrl_image *hdrlWarpedImg, cpl_propertylist *qc_list, cpl_propertylist *pl, cpl_frameset *frameset, const cpl_parameterlist *parlist)
	Compute QC statistics on warped image.
cpl_error_code	eris_ifu_image_add_slit (hdrl_image *hdrlImgFull, const hdrl_image *hdrlImgSlit, int offset)
	Paste slitlet image into full detector image.
cpl_table **	eris_ifu_dist_calc_slitpos (cpl_image **arcImg, cpl_table **centers_array, cpl_table *valid_arc_lines, int productDepth, cpl_boolean *cut_off_left, cpl_boolean *cut_off_right, const cpl_frameset *frameset, const cpl_parameterlist *parlist)
	Calculate slitlet edge positions from arc lamp images.
cpl_error_code	eris_ifu_fit_gauss (const cpl_vector *x, const cpl_vector *y, double *x0, double *sigma, double *area, double *offset)
	Fit Gaussian to find peak center and width.
cpl_vector *	eris_ifu_polyfit_edge (const eris_ifu_vector *x, const eris_ifu_vector *y, int fit_order)
	Iterative polynomial fitting with outlier rejection.
cpl_error_code	eris_ifu_wavecal_processSof_dist (cpl_frameset *frames, int exposureCorrectionMode, int *arcImgCnt, hdrl_imagelist **arcImages, int **lampStates, ifsBand *band, ifsPreopticsScale *scale, ifsInstrument *instrument, double saturation_threhold, cpl_table **qclog)
	Process arc lamp images for distortion calibration.
cpl_error_code	eris_ifu_distortion_reduce_lines (cpl_table *tbl, ifsBand band, int nr_cols)
	Filter valid arc lines by intensity and fit quality.
cpl_error_code	eris_ifu_distortion_reduce_identical_lines (cpl_table *tbl)
	Remove duplicate or overlapping arc lines.
cpl_table *	eris_ifu_dist_wave (cpl_frameset *fs, cpl_table **centers_fitted, int productDepth, cpl_image ***arcImgs, int *imgCnt, const cpl_parameterlist *parlist, cpl_table **qclog)
	Perform wavelength calibration to identify valid arc lines.

Detailed Description

This module provides comprehensive functions for geometric distortion correction in IFU spectrograph data. The distortion correction process involves:

• Detection and fitting of slitlet centers across the detector
• Calculation of 2D polynomial distortion maps for each slitlet
• Image warping to correct geometric distortions
• Bad pixel mask transformation
• Quality control statistics computation

The main workflow includes:

1. Calculate slitlet centers from fiber illumination frames
2. Detect slit edges from arc lamp images
3. Fit 2D polynomials to map distorted to rectified coordinates
4. Warp science images using the distortion maps
5. Transform bad pixel masks accordingly
6. Compute QC statistics on warped images

Note

This module handles both single-fiber and triple-fiber slitlet configurations

Special handling is implemented for edge slitlets that may be cut off

Memory management: Caller is responsible for freeing returned objects

Function Documentation

eris_ifu_dist_calc_centers()

cpl_table ** eris_ifu_dist_calc_centers	(	const hdrl_image *	fibre_div,
		const hdrl_image *	fibre_on,
		int	productDepth
	)

Calculate slitlet centers across the detector.

Parameters

fibre_div	Divided fiber flat field image
fibre_on	Fiber illumination image
productDepth	Debug output level (bit flags)

Returns

Array of SLITLET_CNT tables containing fitted center positions, or NULL on error

This is the main function for determining slitlet center positions:

1. Takes horizontal chunk in middle of detector
2. Collapses in Y to get profile
3. Estimates and fits centers to determine number of traces (32 or 96)
4. Allocates output tables accordingly
5. Processes full detector in chunks from center outward
6. Stores results in per-slitlet tables with columns:
   • Single trace: "x", "y"
   • Triple trace: "x_l", "x", "x_r", "y"

Note

Each element of returned array must be freed with cpl_table_delete()

Array itself must be freed with cpl_free()

Debug files saved if productDepth & 4

Definition at line 785 of file eris_ifu_distortion_static.c.

References BRK_IF_ERROR, BRK_IF_NULL, CATCH, CATCH_MSGS, CHECK_ERROR_STATE, eris_ifu_calc_centers_collapse_chunk(), eris_ifu_dist_calc_centers_copy(), eris_ifu_dist_calc_centers_fit(), eris_ifu_dist_calc_centers_profile(), eris_ifu_free_propertylist(), eris_ifu_free_string(), eris_ifu_free_table(), eris_ifu_free_vector(), eris_ifu_save_vector_dbg(), hdrl_image_get_image_const(), and TRY.

eris_ifu_dist_calc_centers_copy()

cpl_error_code eris_ifu_dist_calc_centers_copy	(	const cpl_vector *	fit_centers,
		int	y_index,
		double	y_value,
		cpl_table **	cen_array
	)

Copy fitted centers to the output table array.

Parameters

fit_centers	Vector of fitted center positions
y_index	Row index in output tables
y_value	Y coordinate value to store
cen_array	Array of output tables (one per slitlet)

Returns

CPL_ERROR_NONE on success, error code otherwise

This function distributes fitted centers into per-slitlet tables:

• For 32 traces: stores center position in "x" column
• For 96 traces: stores left, center, and right traces in "x_l", "x", "x_r" columns
• Handles edge cases where traces run off detector by comparing with neighboring rows

Note

Requires cen_array to be pre-allocated with SLITLET_CNT tables

Special logic handles partial traces at detector edges

Definition at line 586 of file eris_ifu_distortion_static.c.

References BRK_IF_ERROR, BRK_IF_NULL, BRK_WITH_ERROR_MSG, CATCH, CATCH_MSGS, and TRY.

Referenced by eris_ifu_dist_calc_centers().

eris_ifu_dist_calc_centers_fit()

cpl_vector * eris_ifu_dist_calc_centers_fit	(	const cpl_vector *	profile,
		const cpl_vector *	est_centers,
		cpl_boolean	do_fix_cnt
	)

Fit Gaussian profiles to refine center positions.

Parameters

profile	The profile in X across the detector
est_centers	Estimated center positions from peak detection
do_fix_cnt	If TRUE, correct the count to exactly 32 or 96 traces

Returns

Vector with exactly 32 or 96 fitted center values, or NULL on error

This function performs Gaussian fitting to refine center estimates:

• First call (do_fix_cnt=TRUE): Determines correct number of traces (32 or 96)
• Fits Gaussian to each estimated center to get sub-pixel precision
• If more traces detected than expected, uses statistical outlier rejection
• Subsequent calls (do_fix_cnt=FALSE): Handles edge cases where traces run off detector

Outlier rejection strategy:

• Check leftmost and rightmost slitlets separately using median and stddev
• Reject peaks differing by more than thresh*stddev from local median
• Apply stricter global rejection if needed

Note

Returned vector must be freed by caller using cpl_vector_delete()

Function exits with error if less than 32 or 96 valid traces found

Definition at line 371 of file eris_ifu_distortion_static.c.

References BRK_IF_ERROR, BRK_IF_NULL, CATCH, CATCH_MSGS, eris_ifu_dist_estimate_low_slitlet(), eris_ifu_free_ifu_vector(), eris_ifu_free_vector(), eris_ifu_vector_count_non_rejected(), eris_ifu_vector_create(), eris_ifu_vector_extract(), eris_ifu_vector_get(), eris_ifu_vector_get_median(), eris_ifu_vector_get_stdev_median(), eris_ifu_vector_is_rejected(), eris_ifu_vector_reject(), SET_ERROR, and TRY.

Referenced by eris_ifu_dist_calc_centers().

eris_ifu_dist_calc_centers_profile()

cpl_vector * eris_ifu_dist_calc_centers_profile	(	const cpl_vector *	profile,
		cpl_boolean	lowerCutLevel
	)

Detect peak positions from a collapsed profile.

Parameters

profile	Input profile vector (collapsed in Y direction)
lowerCutLevel	If TRUE, use lower threshold for peak detection

Returns

Vector containing detected peak center positions, or NULL on error

This function analyzes a horizontal profile and detects peaks by:

• Computing a dynamic cut level based on profile mean
• Finding left and right edges of peaks above the threshold
• Calculating center positions as (left+right)/2
• Iterating with decreasing thresholds if expected peak count not found
• Sorting peaks by height to remove low-amplitude spurious detections

Note

The function expects to find either SLITLET_CNT (32) or 3*SLITLET_CNT (96) peaks

Returned vector must be freed by caller using cpl_vector_delete()

Border pixels (ERIS_IFU_DETECTOR_BP_BORDER) are ignored in the detection

Definition at line 73 of file eris_ifu_distortion_static.c.

References BRK_IF_ERROR, BRK_IF_NULL, CATCH, CATCH_MSGS, eris_ifu_free_ifu_vector(), eris_ifu_free_vector(), eris_ifu_vector_create(), eris_ifu_vector_get_mean(), and TRY.

Referenced by eris_ifu_dist_calc_centers().

eris_ifu_dist_calc_distortion()

cpl_polynomial ** eris_ifu_dist_calc_distortion	(	cpl_table **	slit_edges,
		cpl_table **	centers,
		int	productDepth,
		cpl_boolean	cut_off_left,
		cpl_boolean	cut_off_right,
		cpl_table **	minmax_borders,
		cpl_propertylist ***	qc,
		cpl_propertylist *	pl,
		cpl_frameset *	frameset,
		const cpl_parameterlist *	parlist
	)

Calculate distortion polynomials for all slitlets.

Parameters

slit_edges	Array of tables with detected slit edge positions
centers	Array of tables with fitted slitlet centers
productDepth	Debug output level
cut_off_left	Indicates if leftmost slitlet is cut off
cut_off_right	Indicates if rightmost slitlet is cut off
minmax_borders	Output: table with min/max border positions per slitlet
qc	Output: array of QC property lists (one per slitlet)
pl	Property list for FITS headers
frameset	Input frameset
parlist	Parameter list

Returns

Array of SLITLET_CNT distortion polynomials, or NULL on error

This function computes 2D polynomial distortion maps:

1. Fits polynomials to edge positions as function of Y
2. Estimates cut-off edges using neighboring slitlet widths
3. Defines target positions in rectified coordinate system
4. Builds 2D grid of (target_x, target_y) -> measured_x
5. Fits 2D polynomial to this mapping
6. Computes QC statistics (slitlet widths, center positions, etc.)

Note

Polynomial degree is 2 in X and 3 in Y

Each polynomial must be freed with cpl_polynomial_delete()

Array must be freed with cpl_free()

QC property lists contain statistics on fitted edges

Definition at line 1136 of file eris_ifu_distortion_static.c.

References ASSURE, BRK_IF_ERROR, BRK_IF_NULL, CHECK_ERROR_STATE, eris_ifu_dist_calc_distortion(), eris_ifu_dist_calc_distortion_fitedge(), eris_ifu_distortion_get_narcs(), eris_ifu_free_ifu_vector(), eris_ifu_vector_add(), eris_ifu_vector_duplicate(), eris_ifu_vector_get_mean(), eris_ifu_vector_new_wrap(), eris_ifu_vector_subtract(), and TRY.

Referenced by eris_ifu_dist_calc_distortion().

eris_ifu_dist_calc_distortion_fillgrid()

cpl_error_code eris_ifu_dist_calc_distortion_fillgrid	(	cpl_bivector *	grid,
		const eris_ifu_vector *	data,
		cpl_vector *	val_to_fit,
		double	x_pos,
		int	n_size,
		int	arc_cnt
	)

Fill grid with distortion mapping data.

Parameters

grid	Output: 2D grid of target coordinates (x, y)
data	Input: fitted edge positions
val_to_fit	Output: measured X positions to fit
x_pos	Target X position for this arc
n_size	Number of data points
arc_cnt	Arc index (for offset in grid)

Returns

CPL_ERROR_NONE on success, error code otherwise

Populates grid and value arrays for 2D polynomial fitting:

• Grid X: all set to x_pos (target coordinate)
• Grid Y: distributed Y coordinates
• Values: measured X positions from fitted data

Note

Rejected values in data are set to NAN in val_to_fit

Definition at line 2449 of file eris_ifu_distortion_static.c.

eris_ifu_dist_calc_distortion_fitedge()

eris_ifu_vector * eris_ifu_dist_calc_distortion_fitedge	(	const cpl_table *	edge,
		const char *	col_name,
		const eris_ifu_vector *	y,
		int	n_calib,
		int	n_size,
		int	fit_order,
		int	slitlet,
		cpl_table *	dbg_tbl
	)

Fit polynomial to single edge as function of Y.

Parameters

edge	Table with edge positions
col_name	Column name containing X positions
y	Y coordinate vector
n_calib	Number of calibration points
n_size	Output vector size (number of Y positions)
fit_order	Polynomial order (typically 2 or 3)
slitlet	Slitlet index for debugging
dbg_tbl	Debug table to store polynomial coefficients

Returns

Vector with fitted edge positions at n_size Y coordinates, or NULL on error

Fits polynomial of form: x(y) = a0 + a1*y + a2*y^2 + ... Returns evaluated positions at regular Y intervals.

Note

Returned vector must be freed with eris_ifu_vector_delete()

Definition at line 2363 of file eris_ifu_distortion_static.c.

Referenced by eris_ifu_dist_calc_distortion().

eris_ifu_dist_calc_distortion_full()

cpl_polynomial ** eris_ifu_dist_calc_distortion_full	(	cpl_table **	slit_edges,
		cpl_table **	centers,
		int	productDepth,
		cpl_boolean	cut_off_left,
		cpl_boolean	cut_off_right
	)

Calculate distortion polynomials (alternative method)

Parameters

slit_edges	Array of tables with detected slit edge positions
centers	Array of tables with fitted slitlet centers
productDepth	Debug output level
cut_off_left	Indicates if leftmost slitlet is cut off
cut_off_right	Indicates if rightmost slitlet is cut off

Returns

Array of SLITLET_CNT distortion polynomials, or NULL on error

Alternative distortion calculation with different polynomial fitting approach. Uses same input data but different target coordinate calculation.

Note

Polynomial degree is 3 in both X and Y

Each polynomial must be freed with cpl_polynomial_delete()

Array must be freed with cpl_free()

Definition at line 1844 of file eris_ifu_distortion_static.c.

eris_ifu_dist_calc_slitpos()

cpl_table ** eris_ifu_dist_calc_slitpos	(	cpl_image **	arcImg,
		cpl_table **	centers_array,
		cpl_table *	valid_arc_lines,
		int	productDepth,
		cpl_boolean *	cut_off_left,
		cpl_boolean *	cut_off_right,
		const cpl_frameset *	frameset,
		const cpl_parameterlist *	parlist
	)

Calculate slitlet edge positions from arc lamp images.

Parameters

arcImg	Array of arc lamp images
centers_array	Array of tables with fitted slitlet centers
valid_arc_lines	Table of valid arc lines (from wavelength calibration)
productDepth	Debug output level
cut_off_left	Output: TRUE if leftmost slitlet is cut off
cut_off_right	Output: TRUE if rightmost slitlet is cut off
frameset	Input frameset
parlist	Parameter list

Returns

Array of SLITLET_CNT tables with detected edge positions, or NULL on error

Detects slit edges for each arc line:

1. For each slitlet, extracts center position
2. For each valid arc line, creates horizontal profile
3. Fits Gaussian to find left and right edges
4. Applies statistical outlier rejection based on slit width
5. Handles edge cases where first/last slitlet extends beyond detector

Output tables contain columns:

• edge_left: X coordinate of left edge
• edge_right: X coordinate of right edge
• slit_width: Distance between edges
• y_pos: Y coordinate of arc line

Note

Each table must be freed with cpl_table_delete()

Array must be freed with cpl_free()

Cut-off flags help subsequent processing handle edge slitlets correctly

Definition at line 3818 of file eris_ifu_distortion_static.c.

eris_ifu_dist_estimate_low_slitlet()

cpl_vector * eris_ifu_dist_estimate_low_slitlet

(

const cpl_vector *

est_centers

)

Estimate position of missing low slitlet.

Parameters

est_centers

Input vector with estimated center positions

Returns

New vector with corrected center positions including estimated missing slitlet, or NULL on error

This function handles cases where peak detection misses a slitlet by:

• Checking if the correct number of slitlets is detected (32 or 96)
• If missing, estimating the position based on neighboring slitlets
• Special handling for the known bad slitlet (#15 in 25mas mode)
• Removing trailing zeros caused by detector edge cutoff

Note

For 25mas scale: looks for missing slitlet around position 15

For 100mas/250mas scales: checks distances between consecutive traces

Returned vector must be freed by caller using cpl_vector_delete()

Definition at line 218 of file eris_ifu_distortion_static.c.

References BRK_IF_ERROR, BRK_IF_NULL, CATCH, CATCH_MSGS, eris_ifu_free_vector(), and TRY.

Referenced by eris_ifu_dist_calc_centers_fit().

eris_ifu_dist_poly_fit_2d_create()

cpl_polynomial * eris_ifu_dist_poly_fit_2d_create	(	cpl_bivector *	xy_pos,
		const cpl_vector *	values,
		double *	msee
	)

Create 2D polynomial fit from grid data.

Parameters

xy_pos	2D grid of (x,y) positions
values	Measured values to fit
msee	Output: mean squared error estimate (optional, can be NULL)

Returns

Fitted 2D polynomial, or NULL on error

Performs 2D polynomial fit with maximum degrees:

• X dimension: degree 2
• Y dimension: degree 3

The polynomial can be evaluated at any (x,y) to get the fitted value.

Note

Returned polynomial must be freed with cpl_polynomial_delete()

NaN values in input are handled by CPL fitting routine

Definition at line 2526 of file eris_ifu_distortion_static.c.

eris_ifu_dist_save_distortion()

cpl_error_code eris_ifu_dist_save_distortion	(	cpl_polynomial **	poly2d,
		const cpl_table *	minmax_borders,
		const char *	fn,
		cpl_frameset *	frameset,
		const cpl_parameterlist *	parlist,
		cpl_propertylist **	qc
	)

Save distortion polynomials to FITS file.

Parameters

poly2d	Array of 2D polynomials (one per slitlet)
minmax_borders	Table with min/max border positions
fn	Output filename
frameset	Input frameset for provenance
parlist	Parameter list for provenance
qc	Array of QC property lists

Returns

CPL_ERROR_NONE on success, error code otherwise

Saves polynomials in FITS table format with:

• One extension per slitlet
• Columns: degx, degy, coeff
• QC parameters in extension headers
• Final extension contains minmax_borders table

Note

Output file can be loaded by eris_ifu_load_distortion_polynomials()

Definition at line 2611 of file eris_ifu_distortion_static.c.

eris_ifu_dist_warp_bpm()

hdrl_image * eris_ifu_dist_warp_bpm	(	const hdrl_image *	bpmIn,
		cpl_polynomial **	poly_u,
		const cpl_table *	borders,
		productDepthType	productDepth
	)

Warp bad pixel mask using distortion polynomials.

Parameters

bpmIn	Input bad pixel mask as HDRL image
poly_u	Array of X-distortion polynomials
borders	Table with slitlet boundaries
productDepth	Debug output level

Returns

Warped bad pixel mask, or NULL on error

Warps bad pixel mask with special handling:

1. Creates column contribution map (each pixel stores its original column number)
2. Warps the contribution map
3. Interpolates BPM values based on fractional contributions
4. Marks border regions as bad where data comes from outside valid detector area

This ensures bad pixels are correctly propagated through geometric transformation.

Note

Returned image must be freed with hdrl_image_delete()

Algorithm accounts for fractional pixel contributions at boundaries

Definition at line 3119 of file eris_ifu_distortion_static.c.

Referenced by eris_ifu_jitter_build_cube().

eris_ifu_dist_warp_image()

hdrl_image * eris_ifu_dist_warp_image	(	const hdrl_image *	imgIn,
		cpl_polynomial **	poly_u,
		const cpl_table *	borders
	)

Warp full detector image by warping each slitlet.

Parameters

imgIn	Input HDRL image
poly_u	Array of X-distortion polynomials (one per slitlet)
borders	Table with l_min/r_max for each slitlet

Returns

Warped full detector image, or NULL on error

Main warping function that:

1. Creates output image of same size as input
2. Warps each slitlet independently
3. Pastes warped slitlets into output at standard positions

This approach is more accurate than full-image warping as it handles discontinuities between slitlets properly.

Note

Returned image must be freed with hdrl_image_delete()

Can be parallelized (warping of different slitlets is independent)

Definition at line 3034 of file eris_ifu_distortion_static.c.

Referenced by eris_ifu_jitter_build_cube().

eris_ifu_dist_warp_image_full()

hdrl_image * eris_ifu_dist_warp_image_full	(	const hdrl_image *	hdrl_img_in,
		cpl_polynomial **	poly_u,
		int	productDepth
	)

Warp full image using distortion polynomials (alternative method)

Parameters

hdrl_img_in	Input HDRL image to warp
poly_u	Array of X-distortion polynomials
productDepth	Debug output level

Returns

Warped HDRL image, or NULL on error

Alternative warping method that processes entire image at once. Uses polynomial_warp with identity Y polynomial.

Note

Returned image must be freed with hdrl_image_delete()

Less efficient than slitlet-wise warping

Definition at line 2805 of file eris_ifu_distortion_static.c.

eris_ifu_dist_warp_slitlet()

hdrl_image * eris_ifu_dist_warp_slitlet	(	const hdrl_image *	imgIn,
		const cpl_polynomial *	poly_u,
		const cpl_polynomial *	poly_v,
		double	l_min,
		double	r_max,
		int	slitletNr
	)

Warp single slitlet.

Parameters

imgIn	Input HDRL image
poly_u	X-distortion polynomial
poly_v	Y-distortion polynomial (typically identity)
l_min	Minimum X coordinate of slitlet
r_max	Maximum X coordinate of slitlet
slitletNr	Slitlet index for diagnostics

Returns

Warped slitlet image (SLITLET_WIDTH x ERIS_IFU_DETECTOR_SIZE_Y), or NULL on error

Extracts and warps a single slitlet:

1. Extracts region from l_min to r_max
2. Applies polynomial warping
3. Trims or pads result to standard SLITLET_WIDTH (64 pixels)

Special handling for slitlets extending beyond detector boundaries.

Note

Returned image must be freed with hdrl_image_delete()

Output width is always SLITLET_WIDTH regardless of input

Definition at line 2923 of file eris_ifu_distortion_static.c.

eris_ifu_dist_warp_stats()

cpl_error_code eris_ifu_dist_warp_stats	(	const hdrl_image *	hdrlWarpedImg,
		cpl_propertylist *	qc_list,
		cpl_propertylist *	pl,
		cpl_frameset *	frameset,
		const cpl_parameterlist *	parlist
	)

Compute QC statistics on warped image.

Parameters

hdrlWarpedImg	Warped image to analyze
qc_list	Output: QC parameters to add to product
pl	Property list for output file
frameset	Input frameset
parlist	Parameter list

Returns

CPL_ERROR_NONE on success, error code otherwise

Computes quality control parameters on warped image:

• Re-detects slitlet centers to verify distortion correction
• Calculates center position statistics (stdev, median)
• Measures slitlet widths
• Saves fitted centers to QC file

QC parameters added per slitlet:

• C STDEV: standard deviation of center position
• C MEDIAN: median center position
• R-L STDEV/MEDIAN: slitlet width statistics
• For triple traces: additional center-left, center-right statistics

Note

Creates intermediate QC file with fitted centers

Definition at line 3356 of file eris_ifu_distortion_static.c.

eris_ifu_dist_wave()

cpl_table * eris_ifu_dist_wave	(	cpl_frameset *	fs,
		cpl_table **	centers_fitted,
		int	productDepth,
		cpl_image ***	arcImgs,
		int *	imgCnt,
		const cpl_parameterlist *	parlist,
		cpl_table **	qclog
	)

Perform wavelength calibration to identify valid arc lines.

Parameters

fs	Frameset with arc images and reference data
centers_fitted	Array of tables with fitted slitlet centers
productDepth	Debug output level
arcImgs	Output: array of arc lamp images
imgCnt	Output: number of images
parlist	Parameter list
qclog	Output: QC log table

Returns

Table of valid arc lines with positions, or NULL on error

Performs simplified wavelength calibration to identify good arc lines:

1. Loads arc lamp images and reference line lists
2. Collapses spectra at slitlet centers
3. Performs first-fit wavelength calibration
4. Fits all lines and computes quality metrics
5. Filters lines by intensity and fit quality
6. Returns table with columns: slitlet, position, wavelength, fit parameters

This provides the list of valid arc lines needed for distortion calibration.

Note

Returned table must be freed with cpl_table_delete()

Uses wavelength calibration to ensure only real arc lines are used

Definition at line 5083 of file eris_ifu_distortion_static.c.

References BRK_IF_ERROR, BRK_IF_NULL, BRK_WITH_ERROR_MSG, CATCH, CHECK_ERROR_STATE, eris_ifu_fit_all_lines(), eris_ifu_free_bivector(), eris_ifu_free_hdrl_imagelist(), eris_ifu_free_image(), eris_ifu_free_polynomial(), eris_ifu_free_propertylist(), eris_ifu_free_table(), eris_ifu_free_vector(), eris_ifu_get_first_fit(), eris_ifu_read_wave_setup(), eris_ifu_wave_clear_tables(), eris_ifu_wave_collapse_slitlet(), eris_ifu_wave_get_firstFitTable(), eris_ifu_wave_get_refLines(), eris_ifu_wave_init_tables(), eris_ifu_wave_save_fitting_tables(), eris_ifu_wave_save_spectrum(), eris_ifu_wavecal_processSof_dist(), hdrl_image_get_image_const(), hdrl_imagelist_get_const(), and TRY.

eris_ifu_distortion_get_narcs()

int eris_ifu_distortion_get_narcs	(	int	i,
		cpl_boolean	triple_traces,
		cpl_boolean	cut_off_left,
		cpl_boolean	cut_off_right
	)

Determine number of arc traces to process for a slitlet.

Parameters

i	Slitlet index
triple_traces	TRUE if 3 traces per slitlet, FALSE if 1
cut_off_left	TRUE if leftmost slitlet is cut off
cut_off_right	TRUE if rightmost slitlet is cut off

Returns

Number of arc traces (3 or 5 for single-fiber, 5 or 7 for triple-fiber)

Counts: left edge + right edge + center line(s) Decrements count if edge slitlet is cut off at detector boundary.

Definition at line 1087 of file eris_ifu_distortion_static.c.

Referenced by eris_ifu_dist_calc_distortion().

eris_ifu_distortion_reduce_identical_lines()

cpl_error_code eris_ifu_distortion_reduce_identical_lines

(

cpl_table *

tbl

)

Remove duplicate or overlapping arc lines.

Parameters

tbl	Table of arc lines (modified in place)

Returns

CPL_ERROR_NONE on success, error code otherwise

Removes lines with identical or very similar wavelengths (< 0.001 difference). When duplicates found, removes both entries to avoid ambiguity.

Note

Processes each slitlet separately

Modifies table in place by erasing rows

Definition at line 5005 of file eris_ifu_distortion_static.c.

References BRK_IF_NULL, CATCH, CATCH_MSGS, CHECK_ERROR_STATE, eris_ifu_free_table(), and TRY.

eris_ifu_distortion_reduce_lines()

cpl_error_code eris_ifu_distortion_reduce_lines	(	cpl_table *	tbl,
		ifsBand	band,
		int	nr_cols
	)

Filter valid arc lines by intensity and fit quality.

Parameters

tbl	Table of fitted arc lines (modified in place)
band	Spectral band (affects thresholds)
nr_cols	Number of columns per slitlet

Returns

CPL_ERROR_NONE on success, error code otherwise

Applies multiple filtering criteria:

1. Removes lines with area below band- and slitlet-specific threshold
2. Removes lines with intensity below threshold
3. Removes lines that failed fitting in >50% of columns
4. Removes lines that appear only once (likely spurious)
5. Keeps only center column for multi-column fits
6. Removes lines with non-zero error codes

Note

Modifies table in place by erasing rows

Thresholds vary by band and slitlet (slitlet #16 has lower thresholds)

Definition at line 4767 of file eris_ifu_distortion_static.c.

References BRK_IF_NULL, CATCH, CATCH_MSGS, CHECK_ERROR_STATE, eris_ifu_free_table(), eris_ifu_get_bandString(), SET_ERROR_MSG, and TRY.

eris_ifu_fit_gauss()

cpl_error_code eris_ifu_fit_gauss	(	const cpl_vector *	x,
		const cpl_vector *	y,
		double *	x0,
		double *	sigma,
		double *	area,
		double *	offset
	)

Fit Gaussian to find peak center and width.

Parameters

x	X coordinates
y	Y values (intensities)
x0	Output: center position
sigma	Output: Gaussian width (positive on success)
area	Output: Gaussian area (positive on success)
offset	Output: background offset level

Returns

CPL_ERROR_NONE on success, error code otherwise

Performs iterative Gaussian fitting:

1. First attempt: fit all 4 parameters (x0, sigma, area, offset)
2. If first fit doesn't converge, fix sigma and area, refit x0 and offset
3. Returns best-fit parameters even if convergence not achieved

Gaussian model: y = offset + (area / sqrt(2*pi*sigma^2)) * exp(-(x-x0)^2 / (2*sigma^2))

Note

Returns -1 for all parameters if fitting completely fails

Convergence issues are handled gracefully; partial results may be returned

Definition at line 4417 of file eris_ifu_distortion_static.c.

Referenced by eris_ifu_slitpos_gauss().

eris_ifu_image_add_slit()

cpl_error_code eris_ifu_image_add_slit	(	hdrl_image *	hdrlImgFull,
		const hdrl_image *	hdrlImgSlit,
		int	offset
	)

Paste slitlet image into full detector image.

Parameters

hdrlImgFull	Full detector image (modified in place)
hdrlImgSlit	Slitlet image to paste
offset	X offset for paste position

Returns

CPL_ERROR_NONE on success, error code otherwise

Copies data, error, and mask from slitlet image into full image at specified offset. Useful for assembling warped image from individual slitlets.

Note

Can be parallelized if different offsets ensure non-overlapping regions

Both images must have same Y dimension (ERIS_IFU_DETECTOR_SIZE_Y)

Definition at line 3715 of file eris_ifu_distortion_static.c.

eris_ifu_polyfit_edge()

cpl_vector * eris_ifu_polyfit_edge	(	const eris_ifu_vector *	x,
		const eris_ifu_vector *	y,
		int	fit_order
	)

Iterative polynomial fitting with outlier rejection.

Parameters

x	X coordinates
y	Y values to fit
fit_order	Polynomial order (1, 2, or 3)

Returns

Vector of polynomial coefficients [a0, a1, a2, ...], or NULL on error

Performs robust polynomial fitting:

1. Fit polynomial to all data
2. Calculate residuals
3. Reject points with residuals > median + 5*stddev
4. Repeat 3 times total

Polynomial form: y(x) = a0 + a1*x + a2*x^2 + a3*x^3

Note

Handles rejected values in input eris_ifu_vector structures

Returned vector must be freed with cpl_vector_delete()

Rejection mask in x and y is synchronized

Definition at line 4522 of file eris_ifu_distortion_static.c.

eris_ifu_stack_warped()

hdrl_imagelist * eris_ifu_stack_warped	(	const hdrl_image *	imgIn,
		const int *	rowIx
	)

Stack warped image into cube format.

Parameters

imgIn	Input warped full-detector image
rowIx	LUT for slitlet ordering

Returns

Image list representing cube (z-axis is spectral), or NULL on error

Transforms 2D warped image into 3D cube by stacking slitlets:

• Each plane in Z corresponds to one wavelength (detector Y coordinate)
• Each plane contains all 32 slitlets side-by-side
• Slitlet order is determined by rowIx mapping

Note

Returned imagelist must be freed with hdrl_imagelist_delete()

No wavelength calibration applied; still in pixel coordinates

Definition at line 3280 of file eris_ifu_distortion_static.c.

eris_ifu_wavecal_processSof_dist()

cpl_error_code eris_ifu_wavecal_processSof_dist	(	cpl_frameset *	frames,
		int	exposureCorrectionMode,
		int *	arcImgCnt,
		hdrl_imagelist **	arcImages,
		int **	lampStates,
		ifsBand *	band,
		ifsPreopticsScale *	scale,
		ifsInstrument *	instrument,
		double	saturation_threhold,
		cpl_table **	qclog
	)

Process arc lamp images for distortion calibration.

Parameters

frames	Input frameset
exposureCorrectionMode	Exposure correction flags
arcImgCnt	Output: number of arc images
arcImages	Output: HDRL imagelist of arc images
lampStates	Output: array of lamp state flags
band	Output: spectral band
scale	Output: preoptics scale
instrument	Output: instrument identifier
saturation_threhold	Saturation threshold for QC
qclog	Output: QC log table

Returns

CPL_ERROR_NONE on success, error code otherwise

Loads and processes arc lamp frames:

• Identifies ON and OFF frames
• Performs exposure corrections
• Combines multiple lamp images if needed
• Extracts instrument configuration

Note

Similar to eris_ifu_wave_get_arc_images() but tailored for distortion

Caller must free arcImages, lampStates

Definition at line 4677 of file eris_ifu_distortion_static.c.

Referenced by eris_ifu_dist_wave().