.. _VISintro:

Introduction
============

The purpose of this section is to describe the data product of the VIS processing function.   
The description present in this section corresponds to the version of the VIS pipeline used in the current processing.

The VIS processing function produces two types of data products: images and catalogues together with calibration data. 
These are produced for both calibrated individual exposures and stacked images. In addition, there are auxiliary pixel data products associated with each of these images: noise map and Flagmap. 
For stacked images, overlapping images are combined to produce contiguous sky coverage at each survey pointing. The dither patterns used are defined in the mission database. 
These final products are delivered to other OUs (MER-SHE-NIR). 

Two calibrated frame product are listed here: DpdVisCalibratedFrame and DpdVisCalibratedQuadFrame. 
The product DpdVisCalibratedQuadFrame is introduced in the PF-14. As a result, the product DpdVisCalibratedFrame is depreciated since this version.

PF version
----------

Many changes are introduced with each PF release. It is important to verify the PF version of your data prior to its use.
The modifications implemented by each version are enumerated in the respective product documentation.

The table below summarises the date of introduction of each major PF release in the On The Fly processing.

+--------------------+----------------+---------------------------------+
| PF version         | Date           | Remarque                        |
+====================+================+=================================+
| PF 13.0            | 2023/07/01     | PV-phase                        |
+--------------------+----------------+---------------------------------+
| PF 14.0            | 2024/02/14     | Survey start                    |
+--------------------+----------------+---------------------------------+
| PF 15.0            | 2024/05/24     | Version used for reprocessing 1 |
+--------------------+----------------+---------------------------------+
| PF 17.0            | 2024/09/23     | DM 10 version, used for Q1      |
+--------------------+----------------+---------------------------------+

VIS data product
----------------

VIS output data product
***********************

========================================= ============================================ 
Data Product                                     Ddp Name               
========================================= ============================================
:ref:`VISCalibratedQuadFrame`                   DpdVisCalibratedQuadFrame    
:ref:`DpdVisCalibratedFrameCatalog`             DpdVisCalibratedFrameCatalog
Not distributed in Q1                           DpdVisStackedFrame
Not distributed in Q1                           DpdVisStackedFrameCatalog
Not distributed in Q1                           DpdVisDiffractionSpikesFocus
Not distributed in Q1                           DpdVisFlagMap
Not distributed in Q1                           DpdVisAnalysisResults
Not distributed in Q1                           DpdVisGhostCatalogue
Not distributed in Q1                           DpdVisPSFModel
========================================= ============================================

VIS calibration data product
****************************

========================================= ============================================ 
Data Product                                     Ddp Name               
========================================= ============================================
Not distributed in Q1                           DpdVisBFEModel
Not distributed in Q1                           DpdVisBloomingModel
Not distributed in Q1                           DpdVisConfigurationFile
Not distributed in Q1                           DpdVisCTICalibrationResults
Not distributed in Q1                           DpdVisCTIModel
Not distributed in Q1                           DpdVisCTITimeEvolutionModel
Not distributed in Q1                           DpdVisDistortionModel
Not distributed in Q1                           DpdVisFileContainer
Not distributed in Q1                           DpdVisGainModel
Not distributed in Q1                           DpdVisGhostModel
Not distributed in Q1                           DpdVisLargeFlatFrame
Not distributed in Q1                           DpdVisMasterBiasFrame
Not distributed in Q1                           DpdVisMasterCIFrame
Not distributed in Q1                           DpdVisMasterDarkFrame
Not distributed in Q1                           DpdVisMasterFlatFrame
Not distributed in Q1                           DpdVisNonLinearityModel
Not distributed in Q1                           DpdVisRONModel
Not distributed in Q1                           DpdVisShutterModel
Not distributed in Q1                           DpdVisStarMask
Not distributed in Q1                           DpdVisTrapPumpingModel
Not distributed in Q1                           DpdVisTrapPumpingResults
Not distributed in Q1                           DpdVisXTalkModel
Not distributed in Q1                           DpdVisZeroPoint
========================================= ============================================


VIS pipeline
------------

The figure below describe the VIS processing.

Input calibration products are shown on the left and output are on the right. 

The first part in the VIS processing function is pixel correction. 

.. figure:: dpcards/images/processQuad-RID_Q1_v04.png

Then we do photometric and astrometric calibration and catalogue extraction.
The output products from this stage are the data products which have been delivered for the Q1 release.

.. figure:: dpcards/images/processExp-RID-Q1_v04_2.png

Stacking of individual exposure is done with this final processing elements.

.. figure:: dpcards/images/stacking-RID_Q1_v04.png