mod_qual (Oct93)               qasun              mod_qual (Oct93)



NAME
    mod_qual -- image quality analysis for  modulation  images.   Images
    are  checked for partial images, distorted images, systematic noise,
    low intensity and bad edges.  The images may be elliptical.
    
    
USAGE
    mod_qual inputl qa_param_fil epoch_time nom_intens (del_image seconds 
            write_head square_side line_length spot_toler edge_toler wave_toler 
            int_toler verbose image_band)
    
    
PARAMETERS
    
    inputl
        input image or list of images
    
    qa_param_fil
        output image of image QA parameters
    
    epoch_time
        string containing the full date and time of time slot  0.   Form
        is "yyyy/mm/dd.hh:mm:ss".
    
    (del_image = 60) 
        integer number of seconds between images.
    
    (seconds = no)
        Should  the  seconds  be  included when computing the image time
        slot?.
    
    (write_head = no)
        Should the history and time slot be written in the image header?
    
    (square_side = 17)
        Number of pixels on a side for the image  spot  checks  and  the
        width of the swaths.
    
    (line_length = 9)
        Number  of  pixels  for  the  line  length  for  the  image edge
        evaluation.
    
    (spot_toler = 0.2)
        Images with any on-disk spot ratio  less  than  (1.0-spot_toler)
        are  flagged  for  examination.   The  on-disk spot ratio is the
        ratio of the intensity in each quadrant  at  half  of  the  disk
        radius to the central intensity.
    
    (edge_toler = 2.)
        Images  with ratios of pixel sums used to check the edge quality
        greater than edge_tol are flagged for examination.
    
    (wave_toler = 0.25)
        Images    with    (horizontal    sigma/vertical     sigma)     <   
        (1.00-wave_toler)   or   (horizontal   sigma/vertical  sigma)  > 
        (1.00+wave_toler) are flagged for examination.
    
    (mod_toler = 0.85)
        Nominal  central  value  of  modulation.   Images  with  average 
        central  modulation  of  modulation  < mod_toler are flagged for
        examination.
    
    (verbose = no)
        Should the ASCII output for unflagged images be written out?
    
    (image_band = 2)
        The number of the modulation band, for three dimensional images.
    
    
IMAGE HEADER WORDS
    
    DATE-OBS
        Date of observation in UT, format yyyy/mm/dd
    
    TIME-OBS
        Time of observation in UT, format hh:mm:ss
    
    FNDLMBXC
        x-direction center of the disk in pixels
    
    FNDLMBYC
        y-direction center of the disk in pixels
    
    FNDLMBMI
        length of the semiminor axis in pixels
    
    FNDLMBMA
        length of the semimajor axis in pixels
    
    FNDLMBAN
        angle between the semimajor axis and the y axis in degrees
    
    SER_SLOT
        This used if the date and time of observation  are  not  present
        under the image header words DATE-OBS and TIME-OBS.
    
    
DESCRIPTION
    Task  MOD_QUAL  flags single images that fall outside the range of a
    set of quality standards.  These  are  (to  be  inserted  in  detail
    later)
    
    
    
EXAMPLES
    1.    Assess  the  image  quality  of  solar  disk  images  in  list 
    mo27may.lis.  The image quality parameter outputs  will  be  written
    to  the  image qam27may.  The ASCII outputs will be collected in the
    file qam27may.dat.  The first available image  has  date  1993/05/27
    and  time 14:27:03.  Note that the time input is for slot 0--in this
    case, one minute before the first image.
    
            qa> mod_qual @mo27may.lis qam27may "1993/05/27.14:26:00" 
                    > qam27may.dat
    
    
    
TIME REQUIREMENTS
    The time requirements  for  the  intensity  QA  on  about  700  GONG
    prototype images on a DECstation 5000/200 is about 5 minutes.
    
    
BUGS and CAUTIONS.
    The  time  slot  fixer  can't  reliably  deal with time changes that
    cross year  boundaries.   The  list  colating  code  list_col  can't
    currently deal with slot numbers above 1440.
    

SEE ALSO
     vel_qual, int_qual