Metadata-Version: 2.1
Name: pyddi
Version: 0.0.3
Summary: Identifies Sources that Require Direction-Dependent Calibration.
Home-page: https://github.com/Sebokolodi/pyddi
Author: Lerato Sebokolodi
Author-email: mll.sebokolodi@gmail.com
License: GNU GPL v3
Description: # pyddi
        
        ### Description 
        
        This tool is designed to identify regions in an image that require direction-dependent calibration. 
         
        ### Installation
        
        Installation from source, working directory where source is checked out
        
            pip install .
        
        This package is available on PYPI, allowing
        
            pip install pyddi
        
        ### The Technique:
        
        This tool carries out the following steps:
        
        1. It searches for pixels in an image/sources in the sky model with high signal-to-noise ratio.   
        2. For computation purposes, pixels separated by a few beams are grouped. The position and intensity of the brightest pixel is returned for each group.  
        3. Computes the local variance around pixels from 2 or sources from 1, and selects those with high local variance.   
        4. If the user provides a PSF image, the PSF is correlated with each source/region. those with high correlation factor are selected.
        5. Lastly, the tool writes out a Tigger model containing the source/pixel positions that made it through step 3 or 4. 
        
            5.1 However, a user can supply an actual sky model and the tool will cross match with above model, and tag sources in this former model as 'dE'.
          
            5.2 Or, alternatively, a user can specify whether they want their actual sky model to be used for the identification rather than pixels from an image, in which case, the sources in the sky model will be updated with tags 'dE'. 
            
            5.3 If a sky model is not supplied, source a model with positions will be returned. This model should not be used for anything except the positions.
        
        ### Implementation  
        
        For help: pyddi  -h    
        
            Finds the direction subject to direction-dependent effects.  
          
            optional arguments:      
               -h, --help            show this help message and exit
               -i IMAGE, --img IMAGE    
                         Image of interest. Required.
               -p PSF_IMAGE, --psf PSF_IMAGE   
                         The psf image. Default=None.
               -c CATALOG, --cat CATALOG   
                          Sky model as LSM/txt. Default=None. Must be in Tigger  
                          format: "#format:name, ra_d, dec_d, i"   
               -fth FLUX_THRESHOLD, --flux-thresh FLUX_THRESHOLD   
                          Flux threshold. Regions in an image with flux > fth *
                          noise are considered. Default=10
               -vth VARIANCE_THRESHOLD, --variance-thresh VARIANCE_THRESHOLD   
                          Local variance threshold. Sources with varinace > vth   
                          * noise are considered. Defautl=5.   
               -vsize VARIANCE_SIZE, --var-size VARIANCE_SIZE   
                          The size of the region to compute the local variance.  
                          E.g vsize=10, gives a region of size = 10 *   
                          resolution. The resolution is in pixels. Default=10   
               -cth CORRELATION_THRESHOLD, --correlation-thresh CORRELATION_THRESHOLD   
                          Correlation threshold. Sources with correlation factor   
                          > cth are considered. Default=0.5    
               -csize CORRELATION_SIZE, --corr-size CORRELATION_SIZE   
                          The size of the region to compute correlation. see   
                          vsize. Default=5   
               -gpix GROUP_PIXELS, --group-pix GROUP_PIXELS   
                          The size of the region to group the pixels, in terms   
                          of psf-size. The psf is in degrees. e.g gpix=20, gives   
                          20xpsf. Default=20   
               -usec USE_CATALOG, --use-cat USE_CATALOG   
                          Use -cat for the identification and not only -i.    
               -o OUTPUT_PREFIX, --outpref OUTPUT_PREFIX    
                          The prefix for the output file containing directions   
                          in RA, DEC both in degrees, and peak flux of the   
                          pixels. Default=None  
        
        Example Run:
        
            pyddi -i examples/kat7restored.fits -c examples/kat7restored.gaul -p examples/kat7psf.fits -vth 10 -cth 0.7 -gpix 50  -usec -o test-output 
        
            
          
         
         
         
         
        
        
Platform: UNKNOWN
Classifier: Intended Audience :: Developers
Classifier: Topic :: Scientific/Engineering :: Astronomy
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Description-Content-Type: text/markdown
