The operation of drizzling each input image needs to be performed twice during processing:
Interfaces to main drizzle functions.
Authors: | |
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Warren Hack | |
License: | |
http://www.stsci.edu/resources/software_hardware/pyraf/LICENSE |
Core routine for performing ‘drizzle’ operation on a single input image All input values will be Python objects such as ndarrays, instead of filenames. File handling (input and output) will be performed by calling routine.
Each input image gets drizzled onto a separate copy of the output frame. When stacked, these copies would correspond to the final combined product. As separate images, they allow for treatment of each input image separately in the undistorted, final WCS system. These images provide the information necessary for refining image registration for each of the input images. They also provide the images that will be succeedingly combined into a median image and then used for the subsequent blot and cosmic ray detection steps.
Aside from the input parameters, this step requires:
- valid input images with SCI extensions
- valid distortion coefficients tables
- any optional secondary distortion correction images
- numpy object (in memory) for static mask
This step produces:
- singly drizzled science image (simple FITS format)
- singly drizzled weight images (simple FITS format)
These images all have the same WCS based on the original input parameters and those provided for this step; specifically, output shape, pixel size, and orientation, if any have been specified at all.
For more information on the science applications of the drizzle task, see the AstroDrizzle Handbook
Other Parameters: | |
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driz_separate : bool (Default = No)
driz_sep_kernel : {‘square’, ‘point’, ‘gaussian’, ‘turbo’, ‘tophat’, ‘lanczos3’} (Default = ‘turbo’)
driz_sep_wt_scl : float (Default = exptime)
driz_sep_pixfrac : float (Default = 1.0)
driz_sep_fillval : int or INDEF (Default = INDEF)
driz_sep_bits : int (Default = 0)
driz_sep_wcs : bool (Default = No)
driz_sep_refimage : str (Default = ‘’)
driz_sep_rot : float (Default = INDEF)
driz_sep_scale : float (Default = INDEF)
driz_sep_outnx : int (Default = INDEF)
driz_sep_outny : int (Default = INDEF)
driz_sep_ra : float (Default = INDEF)
driz_sep_dec : float (Default = INDEF)
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Notes
These tasks are designed to work together seemlessly when run in the full AstroDrizzle interface. More advanced users may wish to create specialized scripts for their own datasets, making use of only a subset of the predefined AstroDrizzle tasks, or add additional processing, which may be usefull for their particular data. In these cases, individual access to the tasks is important.
Something to keep in mind is that the full AstroDrizzle interface will make backup copies of your original files and place them in the OrIg/ directory of your current working directory. If you are working with the stand alone interfaces, it is assumed that the user has already taken care of backing up their original datafiles as the input file with be directly altered.
There are two user interface function for this task, one to allow you to create seperately drizzled images of each image in your list and the other to create one single output drizzled image, which is the combination of all of them:
def drizSeparate(imageObjectList,output_wcs,configObj,wcsmap=wcs_functions.WCSMap)
def drizFinal(imageObjectList, output_wcs, configObj,build=None,wcsmap=wcs_functions.WCSMap)
if configObj[single_step]['driz_separate']:
drizSeparate(imgObjList,outwcs,configObj,wcsmap=wcsmap)
else:
drizFinal(imgObjList,outwcs,configObj,wcsmap=wcsmap)
Examples
Basic example of how to call static yourself from a python command line, using the default parameters for the task.
>>> from drizzlepac import adrizzle
return useful help from a file in the script directory called __taskname__.help
Print out syntax help for running astrodrizzle
Parameters: | |
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file : str (Default = None)
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Apply logic for interpreting final_maskval value...
Merge static or CR mask with mask created from DQ array on-the-fly here.
Interface for running wdrizzle from TEAL or Python command-line.
This code performs all file I/O to set up the use of the drizzle code for a single exposure to replicate the functionality of the original wdrizzle.
Perform drizzle operation on input to create output. The input parameters originally was a list of dictionaries, one for each input, that matches the primary parameters for an IRAF drizzle task.
This method would then loop over all the entries in the list and run drizzle for each entry.
Perform the drizzle operation on a single chip. This is separated out from run_driz_img so as to keep together the entirety of the code which is inside the loop over chips. See the run_driz code for more documentation.
Perform the drizzle operation on a single image. This is separated out from run_driz so as to keep together the entirety of the code which is inside the loop over images. See the run_driz code for more documentation.