Difference between revisions of "Makemask"

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(Created page with '== Help on makemask task: == <pre> Make a mask image from rectangular boxes The mask image must be consistent with a particular visibility file and source select…')
 
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== Help on makemask task: ==
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{{makemask}}
<pre>
 
Make a mask image from rectangular boxes
 
 
 
        The mask image must be consistent with a particular visibility file and source
 
        selection; hence the need to specify the imaging parameters and source
 
        selection.
 
 
 
        If the source image has already been made, then a mask image can be made by:
 
 
 
                Load the image into the viewer
 
                click on tools (top just left of center)
 
                click on Region Manager
 
                make  rectangular and/or polygon areas as needed
 
                save as region file
 
                This region file can substitute as a mask in most application.
 
 
 
        You can also use taskname='clean' with interactive = T to make a mask when the
 
        dirty image is produced.
 
 
 
 
 
        Keyword arguments:
 
        cleanbox -- Cleaning region:
 
                default: [] defaults to inner quarter of image
 
                Two specification types:
 
                Explicit pixel ranges
 
                  example: cleanbox=[[110,110,150,145],[180,70,190,80]]
 
                  cleans two regions defined by the pixel ranges
 
                Filename with pixel values with ascii format:
 
                  <fieldid blc-x blc-y trc-x trc-y> on each line
 
        ----------------------------------------------------------------
 
        vis -- Name of input visibility file
 
                default: none; example: vis='ngc5921.ms'
 
        imagename -- Name of output mask image
 
                default: none; example: imagename='ngc5921.mask'
 
        mode -- Type of selection
 
                default: 'mfs'; example: mode='channel';
 
                Options: 'mfs', channel'
 
        nchan -- Number of channels to select
 
                default: -1 (all); example: nchan=45
 
        start -- Start channel
 
                default=0; example: start=5
 
        width -- Channel width (value > 1 indicates channel averaging)
 
                default=1; example: width=5
 
        step -- Step in channel number
 
                default=1; example: step=2
 
        imsize -- Image size in spatial pixels (x,y)
 
                default = [256,256]; example: imsize=[512,512]
 
        cell -- Cell size in arcseconds (x,y)
 
                default=[0,0] = none; example: cell=[0.5,0.5]
 
        phasecenter -- direction measure  or fieldid for the mosaic center
 
                default: '' (imply field=0 as center); example: phasecenter=6
 
                or phasecenter='J2000 19h30m00 -40d00m00'
 
        stokes -- Stokes parameters to image
 
                default='I'; example: stokes='IQUV';
 
                Options: 'I','IV','IQU','IQUV'
 
        field -- Select field using field id(s) or field name(s).
 
                  [run listobs to obtain the list id's or names]
 
                default: ''=all fields
 
                If field string is a non-negative integer, it is assumed a field index
 
                  otherwise, it is assumed a field name
 
                field='0~2'; field ids 0,1,2
 
                field='0,4,5~7'; field ids 0,4,5,6,7
 
                field='3C286,3C295'; field named 3C286 adn 3C295
 
                field = '3,4C*'; field id 3, all names starting with 4C
 
        spw -- Select spectral window/channels
 
                default: ''=all spectral windows and channels
 
                spw='0~2,4'; spectral windows 0,1,2,4 (all channels)
 
                spw='<2';  spectral windows less than 2 (i.e. 0,1)
 
                spw='0:5~61'; spw 0, channels 5 to 61
 
                spw='0,10,3:3~45'; spw 0,10 all channels, spw 3, channels 3 to 45.
 
                spw='0~2:2~6'; spw 0,1,2 with channels 2 through 6 in each.
 
                spw='0:0~10;15~60'; spectral window 0 with channels 0-10,15-60
 
                spw='0:0~10,1:20~30,2:1;2;3'; spw 0, channels 0-10,
 
                  spw 1, channels 20-30, and spw 2, channels, 1,2 and 3
 
</pre>
 

Latest revision as of 16:32, 18 May 2015