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Isis 2 Documentation


equalizer Documentation

equalizer - Write PDF to correct brightness differences between cubes
EQUALIZER uses the PHOTO_RAD_POINTs from the cube labels to find a
best fit for brightness corrections to remove seams between cubes.  A
procedure is created by this program to apply the corrections to each
of the cubes.

The report written to the log file provides an indication as to how
successful the program was.  It contains a table listing the image
numbers, averages, ratio, difference between the updated averages
(ADD ERR), and 1 - the updated ratio (MULT ERR) for each of the overlap
areas.

The dn values are adjusted as follows:

ADD only:    newdn   =   olddn + ADD
MULT only:   newdn   =   (olddn - photomean)*MULT + photomean
BOTH:        newdn   =   (olddn - photomean)*MULT + photomean + ADD

In the MULT only and BOTH cases, the ADD term absorbs the photomean terms.

PROGRAMMERS: Kay Edwards and Debbie Cook, U.S.G.S.,  Flagstaff, Arizona

ParmDescriptionDefault
FROM
Input cube file names
     or
""
FROMLIST
List of input cube file names
""
HOLD
Hold file names
     or
""
HOLDLIST
List of hold file names
""
TO
Name of PDF to be created
temp.pdf
FITOPT
1  -> MULT
2  ->        ADD
3  -> MULT & ADD
3
TOL
Tolerance for gain ratios
.5
ALPHA
Arbitrary constant for LSF
1000.
MINCOUNT
Minimum number of points in
overlap area required to be
used in the solution.
1000

ADDITIONAL NOTES:

ParmDescription
FROM
List of cubes that are to be compared.  These cubes must
have PHOTO_RAD_POINTs in the labels to be used by this
program.  A maximum of 50 cubes may be listed here.  If more
are needed, use FROMLIST.
FROMLIST
ASCII file containing the list of cubes to be processed by
this program.  List one cube per line.  Up to 1000 cubes may
be listed.
HOLD
List of cubes that are to be held.  The PHOTO_RAD_POINTs in
the labels are used to influence the solution, but the
camera angles are not changed on held images.  A maximum of
50 cubes may be listed here.  If more are needed, use
HOLDLIST.
HOLDLIST
ASCII file containing the list of cubes to be held by this
program.  List one cube per line.  Up to 1000 cubes may be
listed.  See HOLD for more information.
TO
This is the name of a PDF that will be created by this
program.  This PDF will apply the actual corrections to the
cubes using the program "poly".  The input cubes will have
".l4" appended to the file name to create the output file
names.  An additive and a multiplicative factor will be
applied to all cubes that were not held constant.
FITOPT
Choose the fit option to select the algorithm to use to
adjust the pixel values.  Note that due to the nature of the
fit equations, an add will be used in "poly" even when the
MULT only option is selected.
TOL
This value is used to judge the gain ratios between images.
Any point with a ratio outside the range between TOL and
1/TOL is ignored.
ALPHA
An arbitrary constant to remove the indeterminacy of the
least squares solution.  A large ALPHA allows the brightness
values to change more.  A small ALPHA holds closer to the
current brightness values.
MINCOUNT
If the number of points in the overlap area meets or exceeds
this value, the area will go into the solution.  Otherwise
the overlap area will be weighted 0 and essentially ignored.

Last updated: Jan 31 2005
File: pdfs2.html

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