09_0-DRL-Data-Structures.tex

\clearpage
\section{DRL Data Items and Structures}\label{sec:drl_data_structures}
%\TODO{CAVEAT: Section widely TAKEN 1:1 FROM MICADO - TO BE Checked!}


This Section describes the C Data Items and Data Structures that represent inside the C code the FITS input and output files of the recipes. \ac{METIS} follows the approach by MATISSE~\cite{MATISSE-DRLD}, as suggested by the Dataflow for ESO Observatories Deliverables Standard~\cite{1618}.
The conversion between data structures and \ac{FITS} files and vice versa will be implemented using the abstractions provided by \ac{CPL} and \ac{HDRL}. 

Clarification of the terms used (see also~\cite{hdrl-manual}):
\begin{itemize}
    \item \texttt{cpl\_propertylist}: Key-value pairs like \ac{FITS} headers.
    \item \texttt{cpl\_image}: Representation of an image using two arrays of pixels: data, and bad pixels.
    \item \texttt{cpl\_imagelist}: List of \texttt{cpl\_image}s.
    \item \texttt{cpl\_table}: Tabular data like a catalog.
    \item \texttt{hdrl\_image}: Higher level image, with three pixel arrays per image: data, uncertainty, and data quality.
          The \texttt{hdrl\_image} will be used as primary structures to contain image data, because the three pixel arrays map very well to the imaging file formats.
    \item \texttt{hdrl\_imagelist}: List of \texttt{hdrl\_image}s.
    \item \texttt{*}: Pointer to a single instance of a type.
    \item \texttt{* some\_type[]}: Pointer to a list of instances of a type.
\end{itemize}

E.g.
\begin{itemize}
    \item \texttt{cpl\_propertylist * keywords: Primary keywords}: a pointer to the \texttt{cpl\_propertylist} that holds the \ac{FITS} headers of the primary extension,
    \item \texttt{cpl\_propertylist * extkeywords[]: Extension keywords}: a pointer to a list of pointers to \texttt{cpl\_propertylist} instances that hold the \ac{FITS} headers for each extension,
    \item \texttt{hdrl\_image * image: Image}: a pointer to a \texttt{hdrl\_image} instance holding the one image (for the single detector in N and LM, or spanning all detectors for the IFU) of this structure,
    \item \texttt{hdrl\_imagelist * images: Images}: a pointer to a \texttt{hdrl\_imagelist} instance holding all the images (one for each detector) of this structure.
\end{itemize}

There are \ac{DRL} functions for creating, deleting, saving and loading data for each \ac{DRL} data structure when applicable (Sections~\ref{sec:drl_functions_ifu}, \ref{sec:drl_functions_img}, and \ref{sec:drl_functions_lss}).

\input{CalDB_data_items}

\input{LMS_data_items}

\input{IMG_data_items}

\input{LSS_data_items}

\input{ADI_data_items}