IFU Cube Resampling and Combination

Functions
cpl_error_code	eris_ifu_resample_save_cube (hdrl_resample_result *aCube, const char *procatg, const char *recipe, const char *filename, const cpl_parameterlist *parlist, cpl_frameset *frameset, cpl_boolean gen_phase3)
	Save resampled cube to FITS file in DEQ (Data-Error-Quality) format.
cpl_error_code	eris_ifu_cube_collapse_mean_and_save (const char *pro_catg, cpl_frameset *frameset, const cpl_parameterlist *parlist, const char *recipe_name, cpl_boolean apply_flat, cpl_boolean is_pupil)
	-------------------------------------------------------------------------—‍/
cpl_error_code	eris_ifu_combine (cubeType obj_type, cpl_frameset *frameset, const cpl_parameterlist *parlist, const char *recipe_name, const char *pipefile_prefix)
	Resample and combine multiple IFU cubes into a single cube.
cpl_error_code	eris_ifu_resample_trim_edge (hdrl_image *himg, int edge_trim)
	Trim edge pixels from hdrl_image by rejecting them.
cpl_error_code	eris_ifu_combine_pbp (cpl_frameset *frameset, const cpl_parameterlist *parlist, const char *input_cube_pro_catg, const char *filenameSpec, float *offsetx, float *offsety, const char *offunit, const char *recipe_name, const char *pipefile_prefix)
	Resample and combine cubes plane-by-plane (2D spatial resampling per wavelength)

Detailed Description

This module provides functions for resampling and combining IFU data cubes using the HDRL (High-level Data Reduction Library) resampling framework.

The module handles:

• Converting IFU cube data (flux, error, quality) into resampling tables
• Setting up output grids with WCS (World Coordinate System) information
• Configuring various resampling methods (nearest neighbor, linear, quadratic, Renka, Lanczos, drizzle)
• Combining multiple offset cubes into a single resampled cube
• Handling plane-by-plane (2D) and full 3D cube resampling
• Managing edge trimming and bad pixel masking
• Saving resampled products in DFS-compliant FITS format

The resampling process transforms irregularly sampled IFU data onto a regular output grid defined by RA, DEC, and wavelength parameters. This is essential for combining observations with offsets (jitter/dithering) and for generating uniformly sampled data cubes.

Function Documentation

eris_ifu_combine()

cpl_error_code eris_ifu_combine	(	cubeType	obj_type,
		cpl_frameset *	frameset,
		const cpl_parameterlist *	parlist,
		const char *	recipe_name,
		const char *	pipefile_prefix
	)

Resample and combine multiple IFU cubes into a single cube.

Main function for combining multiple offset IFU cubes using HDRL resampling. Converts cube data to resampling tables, sets up the output grid, applies the specified resampling method, and saves the result.

Parameters

obj_type	Cube type (OBJ, STD, PSF, etc.)
frameset	Input frameset containing cubes to combine
parlist	Recipe parameters
recipe_name	Recipe name
pipefile_prefix	Output filename prefix

Returns

CPL_ERROR_NONE on success, error code otherwise

Note

Checks maximum distance between cube centers against threshold

Supports various resampling methods (nearest, linear, Lanczos, drizzle, etc.)

Output saved with DFS-compliant headers and Phase 3 keywords

Edge trimming applied to input cubes if specified

Definition at line 2142 of file eris_ifu_resample.c.

References eris_check_error_code(), eris_ifu_extract_frameset(), eris_ifu_free_propertylist(), eris_ifu_free_string(), eris_ifu_jitter_get_procatg_and_filename(), eris_ifu_resample_save_cube(), eris_ifu_save_image(), hdrl_image_delete(), hdrl_image_get_error(), hdrl_image_get_image(), hdrl_image_get_mask(), hdrl_imagelist_collapse_mean(), hdrl_parameter_delete(), hdrl_resample_compute(), and hdrl_resample_result_delete().

eris_ifu_combine_pbp()

cpl_error_code eris_ifu_combine_pbp	(	cpl_frameset *	frameset,
		const cpl_parameterlist *	parlist,
		const char *	input_cube_pro_catg,
		const char *	filenameSpec,
		float *	offsetx,
		float *	offsety,
		const char *	offunit,
		const char *	recipe_name,
		const char *	pipefile_prefix
	)

Resample and combine cubes plane-by-plane (2D spatial resampling per wavelength)

Combines multiple IFU cubes by resampling each wavelength plane independently in 2D spatial coordinates. This approach is used when full 3D resampling would exceed size limits or when spatial-only resampling is preferred.

Parameters

frameset	Input frameset containing cubes
parlist	Recipe parameters
input_cube_pro_catg	Product category of input cubes
filenameSpec	Output filename suffix
offsetx	User-defined X offsets (or NULL)
offsety	User-defined Y offsets (or NULL)
offunit	Offset units ("pix" or "arcsec")
recipe_name	Recipe name
pipefile_prefix	Output filename prefix

Returns

CPL_ERROR_NONE on success, error code otherwise

Note

Each wavelength plane is resampled independently in RA-DEC space

Output cube has same wavelength sampling as inputs

More memory efficient than full 3D resampling for large cubes

Exposure time maps are computed for flux calibration

Definition at line 2462 of file eris_ifu_resample.c.

References eris_check_error_code(), eris_ifu_extract_frameset(), eris_ifu_free_string(), eris_ifu_resample_save_cube(), eris_ifu_resample_trim_edge(), eris_ifu_save_deq_image(), eris_ifu_save_image_phase3(), eris_pfits_get_dit(), eris_pfits_get_ndit(), hdrl_image_create(), hdrl_image_delete(), hdrl_image_duplicate(), hdrl_image_get_error(), hdrl_image_get_image(), hdrl_image_get_mask(), hdrl_image_get_median(), hdrl_image_reject_from_mask(), hdrl_image_sub_scalar(), hdrl_imagelist_collapse_mean(), hdrl_imagelist_delete(), hdrl_imagelist_get_const(), hdrl_imagelist_new(), hdrl_imagelist_set(), hdrl_parameter_delete(), hdrl_resample_compute(), hdrl_resample_image_to_table(), and hdrl_resample_result_delete().

Referenced by eris_stdstar_reduction_common().

eris_ifu_cube_collapse_mean_and_save()

cpl_error_code eris_ifu_cube_collapse_mean_and_save	(	const char *	pro_catg,
		cpl_frameset *	frameset,
		const cpl_parameterlist *	parlist,
		const char *	recipe_name,
		cpl_boolean	apply_flat,
		cpl_boolean	is_pupil
	)

-------------------------------------------------------------------------—‍/

‍** ‍**

Collapse cube along wavelength axis to mean image and save with QC parameters

Loads a cube from frameset, performs mean collapse along the wavelength (Z) axis, and saves the resulting 2D image in DEQ format. For pupil frames, computes QC parameters for pupil centering shifts. Optionally creates an exposure map at the central wavelength plane.

Parameters

pro_catg	Cube product category tag
frameset	Input frameset containing the cube
parlist	Recipe parameters
recipe_name	Recipe name for output file naming
apply_flat	If TRUE, creates exposure map at central wavelength
is_pupil	If TRUE, computes and adds pupil shift QC parameters

Returns

CPL_ERROR_NONE on success, error code otherwise

Note

Output filenames depend on pro_catg: *_obj_cube_mean.fits, *_std_cube_mean.fits, etc.

Exposure map output: <recipe_name>_exposure_map.fits

For pupil frames: adds QC PUPIL0 SHIFTX/SHIFTY keywords (offset from center in pixels)

NaN values and bad pixels are rejected before collapse

Edge trimming is applied if specified in recipe parameters

Definition at line 1752 of file eris_ifu_resample.c.

References eris_check_error_code(), eris_ifu_free_propertylist(), eris_ifu_resample_trim_edge(), eris_ifu_save_deq_image(), eris_ifu_save_image_phase3(), eris_pfits_get_dit(), eris_pfits_get_ndit(), eris_pfits_put_qc(), eris_qclog_add_double_f(), eris_qclog_init(), hdrl_image_create(), hdrl_image_delete(), hdrl_image_get_error(), hdrl_image_get_image(), hdrl_image_get_mask(), hdrl_image_get_size_x(), hdrl_image_get_size_y(), hdrl_image_reject_from_mask(), hdrl_imagelist_collapse_mean(), hdrl_imagelist_create(), and hdrl_imagelist_delete().

Referenced by eris_stdstar_reduction_common().

eris_ifu_resample_save_cube()

cpl_error_code eris_ifu_resample_save_cube	(	hdrl_resample_result *	aCube,
		const char *	procatg,
		const char *	recipe,
		const char *	filename,
		const cpl_parameterlist *	parlist,
		cpl_frameset *	frameset,
		cpl_boolean	gen_phase3
	)

Save resampled cube to FITS file in DEQ (Data-Error-Quality) format.

Saves the resampled cube produced by HDRL to a multi-extension FITS file with:

• Primary HDU: Empty with header only
• Extension 1 (DATA): Data cube
• Extension 2 (ERRS): Error cube (RMSE type)
• Extension 3 (QUAL): Quality/bad pixel map cube (16-bit flags)

The function handles proper header construction including WCS, PRODCATG keywords, and optional Phase 3 metadata.

Parameters

aCube	HDRL resampling result containing cube and header
procatg	FITS product category (e.g., "OBJ_CUBE_COMBINED")
recipe	Recipe name
filename	Output FITS filename
parlist	Input recipe parameters
frameset	Input frameset for DFS product saving
gen_phase3	If TRUE, add ESO Phase 3 compliant keywords

Returns

CPL_ERROR_NONE on success, error code otherwise

Note

CDELT3 keyword is removed and replaced with CD3_3

CUNIT3 is set to "um" (microns) if not present

BUNIT is set to default ADU units if not present

The cube is saved in native data type (preserving precision)

Definition at line 900 of file eris_ifu_resample.c.

References eris_check_error_code(), eris_ifu_free_propertylist(), eris_ifu_heades_add_hduclass_common(), eris_ifu_heades_add_hduclass_data(), eris_ifu_heades_add_hduclass_errs(), eris_ifu_heades_add_hduclass_qual(), eris_ifu_sdp_properties_collect(), eris_ifu_sdp_properties_delete(), eris_ifu_sdp_properties_update(), and eris_ifu_split3_hdrl_imagelist().

Referenced by eris_ifu_combine(), and eris_ifu_combine_pbp().

eris_ifu_resample_trim_edge()

cpl_error_code eris_ifu_resample_trim_edge	(	hdrl_image *	himg,
		int	edge_trim
	)

Trim edge pixels from hdrl_image by rejecting them.

Rejects edge_trim pixels from all four edges of the image by marking them as bad pixels in the hdrl_image bad pixel mask.

Parameters

himg	HDRL image to be trimmed (modified in place)
edge_trim	Number of pixels to trim from each edge

Returns

CPL_ERROR_NONE on success, error code otherwise

Note

If edge_trim >= half the image size, edge_trim is reset to 0 with warning

Uses FITS pixel convention (1-indexed)

Image data is not deleted, just marked as bad

Definition at line 2387 of file eris_ifu_resample.c.

References eris_check_error_code(), hdrl_image_get_size_x(), hdrl_image_get_size_y(), and hdrl_image_reject().

Referenced by eris_ifu_combine_pbp(), and eris_ifu_cube_collapse_mean_and_save().