int_qual (Oct93) qasun int_qual (Oct93)
int_qual -- image quality analysis for intensity images. Images
are checked for partial images, distorted images, systematic noise,
low intensity and bad edges. The images may be elliptical.
int_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)
input image or list of images
output image of image QA parameters
string containing the full date and time of time slot 0. Form
minimum acceptable intensity at the center of the disk.
(del_image = 60)
integer number of seconds between images.
(seconds = no)
Should the seconds be included when computing the image time
(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
(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.
(int_toler = 0.5)
Images with central intensity of (intensity/nom_intens <
int_toler) are not subjected to any tests beyond the partial
(verbose = no)
Should the ASCII output for unflagged images be written out?
(image_band = 3)
The number of the intensity band, for three dimensional images.
IMAGE HEADER WORDS
Date of observation in UT, format yyyy/mm/dd
Time of observation in UT, format hh:mm:ss
x-direction center of the disk in pixels
y-direction center of the disk in pixels
length of the semiminor axis in pixels
length of the semimajor axis in pixels
angle between the semimajor axis and the y axis in degrees
This used if the date and time of observation are not present
under the image header words DATE-OBS and TIME-OBS.
Task INT_QUAL flags single images that fall outside the range of a
set of quality standards. These are (to be inserted in detail
1. Assess the image quality of solar disk images in list
in27may.lis. The image quality parameter outputs will be written
to the image qai27may. The ASCII outputs will be collected in the
file qai27may.dat. The nominal central intensity is 1.0e6. 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> int_qual @in27may.lis qai27may "1993/05/27.14:26:00" 1.0e6
2. Assess the image quality of solar disk images in list
mtw10june.lis. The image quality parameter outputs will be written
to the image qaimtw10june. The ASCII outputs will be collected in
the file qaimtw10june.dat. The nominal central intensity is
1.2e6. The first available image has date 1992/06/10 and time
14:00:15. The images are 75 seconds apart, and the seconds in the
image time stamp should not be ignored. However, the time slot
numbers have already been inserted because the image time stamp is
not under the usual image header words. Note that the time input
is for slot 0--in this case, 75 seconds before the first image.
The intensity is in band 1 of the input image
qa> int_qual @mtw10june.lis qaimtw10june "1992/06/10.13:59:00" 1.2e6
del_image=75 image_band=1 > qaimtw10june.dat
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.