ISIS 3 Application Documentation
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Finds the gaps in a given Cube.
Description
Categories
Groups
Examples
History
Description
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.
Categories
Parameter Groups
Files
| Name | Description |
|---|---|
| FROM | Input cube file |
| TO | Output cube file |
| LOG | The output file of the list of gaps (.pvl, .prt, or .txt). |
Correlation Coefficient Tolerance
| Name | Description |
|---|---|
| CORTOL | Correlation Tolerance |
Buffer Size (Lines)
| Name | Description |
|---|---|
| ABOVE | Number of nulled lines above gaps. |
| BELOW | Number of nulled lines below gaps |
Files: FROM
Description
Input cube file to be checked for line gaps.
| Type | cube |
|---|---|
| File Mode | input |
| Filter | *.cub |
Files: TO
Description
The resulting cube with a null buffer above and below each gap. Enter "TO=none" if you do not want to output a modified cube.
| Type | cube |
|---|---|
| File Mode | output |
| Default | none |
| Filter | *.cub |
Files: LOG
Description
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.
| Type | filename |
|---|---|
| File Mode | output |
| Default | none |
| Filter | *.txt *.prt *.pvl |
Correlation Coefficient Tolerance: CORTOL
Description
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).
| Type | double |
|---|---|
| Default | 0.0 |
Buffer Size (Lines): ABOVE
Description
This parameter specifies how many lines above the gap are set to null in the output cube.
| Type | integer |
|---|---|
| Default | 7 |
Buffer Size (Lines): BELOW
Description
This parameter specifies how many lines below the gap are set to null in the output cube.
| Type | integer |
|---|---|
| Default | 7 |
Examples
Example 1
Finds Image Gaps
Description
Command Line
Input Image
I02025005RDR.cub
|
A section of the input cube
Parameter Name:
FROM This image shows three null gaps. |
Data File
| logFileResults.txt |
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. |
History
| Christopher Austin | 2007-11-26 | Original version |
| Steven Lambright | 2008-05-12 | Removed references to CubeInfo |
| Kimberly Oyama and Steven Lambright | 2012-06-15 | 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. |