ChangeLog for HDRL (High-level Data Reduction Library)
======================================================

The entries below summarize notable changes per release.
Dates are in GNU format (YYYY-MM-DD).

2026-06-02  The HDRL Team

	* Resampling: Fixed PIPE-12792 bug where rotated WCS (with
	  significant off-diagonal CD matrix terms) caused unreasonably
	  large output grid dimensions and memory allocation failures.
	  The fix automatically corrects pixel scale values (delta_ra/
	  delta_dec) when they are incorrectly extracted using only
	  diagonal CD matrix elements, ensuring proper computation
	  accounting for rotation.
	* Barycentric correction: wavelength shift to compensate for
	  observer motion with respect to the solar system barycenter;
	  implementation uses the ERFA library (IAU SOFA-derived).
	* Build system: GSL added as direct dependency for unit tests
	  (limiting magnitude module); ERFA and libcurl added as
	  dependencies for barycentric correction and related functionality.

2021-09-30  The HDRL Team

	* Limiting magnitude: computation as defined in the ESO Phase 3
	  Standard (magnitude of an unresolved source with flux 5 times
	  the noise background).
	* Statistics: added mode of a distribution for collapsing
	  imagelists and image statistics; error from data via analytic
	  or bootstrap Monte Carlo; mean, weighted mean, min-max
	  rejected mean, kappa-sigma clipped mean, median, mode now
	  supported.
	* API: hdrl_overscan_parameter_create_parlist() and
	  hdrl_collapse_parameter_create_parlist() now require an
	  additional default mode parameter.

2021-02-12  The HDRL Team

	* Resampling: 2D images and 3D cubes onto a common grid; six
	  interpolation methods (Nearest, Linear, Quadratic, Renka,
	  Drizzle, Lanczos).
	* Catalogue: pixels with value exactly 0 no longer automatically
	  added to the confidence map as bad; behaviour removed for
	  clearer control.

2018-10-01  The HDRL Team

	* Fixed pattern noise: detection via power spectrum (e.g. pick
	  noise, quasi-periodic patterns).
	* Documentation: corrected description of Strehl ratio variables
	  m1_radius and m2_radius (code was already correct).
	* Spectral efficiency: fixed sign error in atmospheric
	  correction (equation and code).

2018-04-01  The HDRL Team

	* Strehl ratio: computation for AO-assisted instrumentation
	  quality control (peak intensity vs diffraction-limited).
	* Spectral efficiency: as a function of wavelength from flux
	  standard stars vs reference spectrum.
	* Spectral response: telluric correction (optional) and response
	  calculation as a function of wavelength.
	* Differential atmospheric refraction: Filippenko (1982) algorithm
	  with Owens formula for water vapour pressure.
	* Effective air mass computation.

2017-04-01  The HDRL Team

	* Object catalogue generation: astrometric and photometric
	  calibration; local sky background estimation, object/blend
	  detection (Irwin 1985), parametrisation (astrometry,
	  photometry, shape analysis).

2015-11-26  The HDRL Team

	* Fringe correction: master-fringe image via Gaussian mixture
	  model; scaled master used to remove fringes from single images.

2015-05-01  The HDRL Team

	* Master flatfield: algorithms to derive master flatfield.
	* Strehl ratio: initial implementation.

2014-12-15  The HDRL Team

	* Clipping: sigma clipping now uses scaled Median Absolute
	  Deviation (MAD) instead of interquartile range (IQR) for
	  robust RMS; better for low-number statistics and high
	  fraction of affected pixels (e.g. cosmic rays).
	* Library integration: pipeline integration details updated
	  in documentation.

2014-09-17  The HDRL Team

	* Bad pixel detection: various methods for bad pixel detection
	  (see bad-pixel module documentation).

2013-11-29  The HDRL Team

	* First prototype release of the HDRL library.

2013-08-09  The HDRL Team

	* Master bias and master dark computation and handling.

2013-04-26  The HDRL Team

	* Overscan computation and correction.
