ISIS Application Documentation
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Apply a minimum or maximum filter to a cube
Description
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History
V1 V2 V3 V4 V5 V6 V7 V8 V9the program will first substitute an extremely high or low internal value for ISIS. This essentially zeroes out the process in such a way that one of the values in the current boxcar will be supplied as the output pixel, instead of an output pixel from a previous boxcar. Assume that the MAX option is being used on the model boxcar shown above.This value is then compared to the first pixel in the boxcar. This would be the value substituted for "V1". If V1 is greater than the internal value (this will be the case unless V1 is a special pixel) then the new output pixel will tenatively be set to V1. V1 is then compared to V2, and the greater pixel is again set to the temporary maximum. This process continues until the temporary maximum is compared to all of the values in the boxcar, at which point it is set as the output value.
Name | Description |
---|---|
FROM | Input cube |
TO | Output cube |
Name | Description |
---|---|
LINES | Boxcar Lines |
SAMPLES | Boxcar Samples |
Name | Description |
---|---|
FILTER | Type of filter (minimum, maximum) |
Use this parameter to select the filename. All bands within the file will have the filter applied.
Type | cube |
---|---|
File Mode | input |
Filter | *.cub |
This file will contain the filtered output.
Type | cube |
---|---|
File Mode | output |
Pixel Type | real |
Use this parameter to select the number of lines in the boxcar. Higher values take longer, and intensify the results in the vertical direction. The default value is three.
Type | integer |
---|---|
Default | 3 |
Minimum | 1 (inclusive) |
Use this parameter to select the number of samples in the boxcar. Higher values take longer, and intensify the results in the horizontal direction. The default value is three.
Type | integer |
---|---|
Default | 3 |
Minimum | 1 (inclusive) |
Use this parameter to choose the filter type. The possibilities include min, which finds the lowest DN in the boxcar and max, which finds the highest DN in the boxcar.
Type | string | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Default | MIN | |||||||||
Option List: |
|
Minimum 3x3
Example GUI Screenshot of the GUI with parameters set to perform the minimum filter with a 3 x 3 boxcar. |
Input image before minmax.
Parameter Name:
FROM This is the image as it was taken originally. Take note of the size of areas with high DNs, such as on top of mountains and in the lower right corner of the image. |
Output image after minmax
Parameter Name:
TO The filtered image. A side-effect of the program is a slight blur to the image, but notice the change in the details described above. the mountain tops have lost some area, while the dark region at the base has expanded. Also note the reduced intensity of the brightness in the lower right corner. |
Maximum 2x2
Example GUI Screenshot of the GUI with parameters set to perform the maximum filter with a 2 x 2 boxcar. |
Input image before minmax.
Parameter Name:
FROM This is the image as it was taken originally. Take note of the size of areas with high DNs. In particular, notice the man-made lights in the lower right corner of the image and the bright spots on top of the mountain. |
Output image after minmax
Parameter Name:
TO The filtered image. Just as in example 1, the image is blurred slightly. Unlike the first example, bright areas are now enlarged and the brightness that would have been shrunk using the minimum filter is now expanded. Again, note the peaks of the mountains and the man-made lights in the lower right corner. |
Drew Davidson | 2004-07-23 | Original version |
Drew Davidson | 2004-07-26 | Added application test |
Drew Davidson | 2004-08-16 | Added examples |