This program finds gaps in the line direction of an image, and will report the gap
information or expand the gap based on user parameters or default settings. Gaps are areas where
the entire line consists of NULL pixel values or pixel values statistically below the threshold
setting of the CORTOL parameter. This program ignores single line gaps.If the LOG parameter is
specified, the starting and last line of each gap as well as the band number is recorded and
placed into a log filename (.pvl, .txt) entered by the user. If the output cube or TO
parameter is not specified, then the program only identifies the gaps.
The CORTOL parameter should be set to "0.0" to only identify an entire line of "NULL" pixels
as a gap. If the CORTOL parameter is set to a value greater than "0.0," then the statistics of
the current line are compared against the statistics of the previous line to determine if the
line should be considered a gap. This option is useful if random lines are much brighter or
darker than the adjacent lines.
Added the option to nullify a gap and add a buffer of null lines above and below each gap and
output these results to a cube. If no output cube is specified results will only be output to
a log file (.pvl, .prt, or .txt) or vice versa. Neither output affects the other. Fixes #582.
The output file to which all of the gap information is written. If left as the default,
no log file will be created/updated. This file will not be affected by the nulled lines
that are included in the output cube.
This parameter determines how similar one line can be to the next and still be considerd
part of a gap. A higher tolerance will result in gaps that are
more similar to the surrounding area (possibly valid data). A tolerance
closer to zero will result in gaps that are more different from the
surrounding area (CORTOL=0.0 will give you gaps of null data).
In the case of no gaps, the LOG output file
parameter will be empty.
When there are gaps in the cube image, then the gap information is reported in the
LOG file if it is specified. In this example, that file is logFileResults.txt, as shown
here. Each gap is displayed as a group consisting of the band number, the starting line
number, the correlation coefficient that defined the line as gap, and the last line for
a particular gap.
Output Image
cubeResults.cub
The same section as that shown for the input image.
Parameter Name:
TO
This is the image cubeResults.cub that has null lines above and below each gap. You can
see that 10 lines above and below the gap have been nulled out. The narrow strip of
valid data in the middle of the image has been set to null due to the ABOVE and BELOW
parameter settings. Reduce the value for ABOVE and BELOW to minimize the lines being set
to NULL.
