fvc_image

Overview

This is the image data from the DESI fiber view camera.

Creators

  • PlateMaker testing and simulation
    • nfssim

Users

Contents

Image data

These data comprise one image

Storage and access

Through DOS

After the seqid is set, the set and get PML commands may be used to provide PlateMaker with the targets, and retrieve them back if wanted.

First, a PML connection must be established:

>>> from DOSlib.PML import dos_connection
>>> pm = dos_connection('PLATEMAKER')
>>> pm.execute('configure')
'SUCCESS'

and same sample data loaded:

>>> from PlateMaker import test_data
>>> fvc_image = test_data.fvc_image

The python represnation shall be a FITS dictionary, in which keyword/value pairs are stored directly. The image itself shall be stored as a numpy ndarray assigned to the data keyword of this dictionary:

>>> fvc_image['data'].dtype
dtype('uint16')
>>> fvc_image['data'].shape
(6000, 6000)

We need to set the seqid in PlateMaker to prepare it for working on a sequence:

>>> pm.execute('set', seqid=test_data.seq_id)
'SUCCESS'

Then we can set targets:

>>> pm.execute('set', fvc_image=fvc_image)
'SUCCESS'

and get them back (not generally useful):

>>> retrieved_fvc_image = pm.execute('get', 'fvc_image')

Preferred file representation

Name template:fvc-${SEQID}.{CONFIG_ID}.fits
Format:FITS

The FITS image has only primare HDU, which includes the image data.

Example FITS header for HDU0

::
>>> import astropy.io.fits as fits
>>> from PlateMaker import test_data
>>> fname = test_data.data_dir + '/fvc-52254.1.fits'
>>> hdus = fits.open(fname)
>>> hdus[0].header 
SIMPLE  =                    T
BITPIX  =                   16
NAXIS   =                    2
NAXIS1  =                 6000
NAXIS2  =                 6000
BZERO   = 3.27680000000000E+04
BSCALE  = 1.00000000000000E+00