ISIS Application Documentation
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Apply spectral low pass filter to a cube
| Overview | Parameters | Example 1 | Example 2 |
Description
This program applies a spectral low pass filter to a cube. A spectral filter
works between bands as opposed to a spacial operation on a single band.
Lowpass filter means it will be subtracting the average from the original
pixel.
CategoriesRelated Applications to Previous Versions of ISISThis program replaces the following application existing in previous versions of ISIS:
Related Objects and DocumentsApplicationsHistory
|
| U.S. Department of the Interior | U.S. Geological Survey ISIS | Privacy & Disclaimers | Astrogeology Research Program To contact us, please post comments and questions on the USGS Astrogeology Discussion Board To report a bug, or suggest a feature go to: ISIS Github File Modified: 02/21/2025 21:48:39 |
Parameter GroupsFiles
Boxcar Size
Boxcar Settings
|
| U.S. Department of the Interior | U.S. Geological Survey ISIS | Privacy & Disclaimers | Astrogeology Research Program To contact us, please post comments and questions on the USGS Astrogeology Discussion Board To report a bug, or suggest a feature go to: ISIS Github File Modified: 02/21/2025 21:48:39 |
Files: TO
Description
The resultant filtered cube
| Type | cube |
|---|---|
| File Mode | output |
| Filter | *.cub |
Boxcar Size: BANDS
Description
This is the total number of bands in the boxcar. It must be odd and can not exceed twice the number of bands in the cube. In general, the size of the boxcar does not cause the program to operate significantly slower.
| Type | integer |
|---|---|
| Minimum | 1 (inclusive) |
| Odd | This value must be an odd number |
Boxcar Settings: LOW
Description
Valid minimum pixel value that will be used in boxcar computation. If a pixel value is less than LOW then it will not be used when computing the average.
| Type | double |
|---|---|
| Internal Default | Use all pixels |
| Less Than | HIGH |
Boxcar Settings: HIGH
Description
Valid maximum pixel value that will be used in boxcar computation. If a pixel value is greater than HIGH then it will not be used when computing the average.
| Type | double |
|---|---|
| Internal Default | Use all pixels |
| Greater Than | LOW |
Example 1Example of usage of the spectral lowpass filter. Description
This example shows a spectral lowpass filter being applied to the image
with a 5 depth boxcar. This cube has 256 bands so 5 is relatively small.
Although no averaging is done within a single band, the averaging of the
pixels of many bands will cause some averaging and smoothing of the
image if there is much difference between bands. Here is an image which
highlights which pixels a single pass would average. The image shows a
9x9 dot instead of a single pixel highlighted to make it more visible.
In this picture the boxcar would be seven or more bands, with the output
pixel being one of the visible pixels. Depending on how large the boxcar
was many of the values taken in could not be original, at a minimum, one
value will be mirrored since there are only six available bands.
Command Line
speclowpass
from=/work1/mboyd/CM_1514302573_1.cub to=/work1/mboyd/postlow.cub
bands=5
This example will filter the image using 5 bands and no limits on high
or low.
GUI Screenshot
Input Image
Output Image
|
![This program's GUI](javascript:popUpNewWindow ("assets/images/slowpassgui.jpg",533, 477))
![The image graph before the filter](javascript:popUpNewWindow ("assets/images/prelow.jpg",750, 298))
![The image graph after the filter](javascript:popUpNewWindow ("assets/images/postlow.jpg",750, 298))
| U.S. Department of the Interior | U.S. Geological Survey ISIS | Privacy & Disclaimers | Astrogeology Research Program To contact us, please post comments and questions on the USGS Astrogeology Discussion Board To report a bug, or suggest a feature go to: ISIS Github File Modified: 02/21/2025 21:48:39 |
Example 2Example of usage of the spectral lowpass filter. Description
This example shows a spectral lowpass filter being applied to the image
with a 61 depth boxcar. This cube has 256 bands so 61 takes in over a
fifth. Although no averaging is done within a single band, the averaging
of the pixels of many bands will cause some averaging and smoothing of
the image if there is much difference between bands. In this case a
blurry image begins to show through.
Command Line
speclowpass
from=/work1/mboyd/CM_1514302573_1.cub to=/work1/mboyd/postlow.cub
bands=61
This example will filter the image using 61 bands and no limits on
high or low.
GUI Screenshot
Input Image
Output Image
|
![This program's GUI](javascript:popUpNewWindow ("assets/images/gui2.jpg",533, 477))
![The image graph after the filter](javascript:popUpNewWindow ("assets/images/post61.jpg",750, 298))
| U.S. Department of the Interior | U.S. Geological Survey ISIS | Privacy & Disclaimers | Astrogeology Research Program To contact us, please post comments and questions on the USGS Astrogeology Discussion Board To report a bug, or suggest a feature go to: ISIS Github File Modified: 02/21/2025 21:48:39 |