This program applies a spectral division filter to a cube. A spectral filter
works between bands as opposed to a spacial operation on a single band. As a
division filter, it divides the original pixel by the average.
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.
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.
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.
This example shows a spectral division filter being applied to the image
with a 15 depth boxcar. This cube has 256 bands so 15 is relatively
small. No averaging is done between bands, the divisoin filter more
increases differences between bands. Here is an image which highlights
which pixels a single pass would influence. 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.
This example will filter the image using 15 bands and no limits on
high or low.
GUI Screenshot
This program's GUI
Example GUI
Screenshot of the GUI with parameters set to perform the
specdivision filter with a 15 band boxcar on the image
CM_1514302573_1.ir.cub.
Input Image
The image graph before the filter
Input image spectral graph before specdivfilter
Parameter Name:
FROM
This is the spectral plot of the center point of the image, (32,
32), and shows all bands, 1- 256. No filter has been applied, and
the graph clearly shows how the value of line 32 sample 32 differs
from band to band.
Output Image
The image graph after the filter
Output image spectral graph after being filtered
Parameter Name:
TO
This is the image after the filter. First note the change in scale,
everything has been amplified. Even in the apparent flat area small
differences have been amplified.
Example 2
Example of usage of the spectral division filter.
Description
This example shows a spectral division filter being applied to the image
with a 61 depth boxcar. This cube has 256 bands so 61 takes in over a
fifth. In this case an image begins to show through, however, this is
not because of average but because of amplificatino of differences from
the original.
This example will filter the image using 61 bands and no limits on
high or low.
GUI Screenshot
This program's GUI
Example GUI
Screenshot of the GUI with parameters set to perform the
spechighpass filter with a 61 band boxcar on the image
CM_1514302573_1.ir.cub.
Input Image
The image graph before the filter
Input image spectral graph before spectral division filter
Parameter Name:
FROM
This is the spectral plot of the center point of the image, (32,
32), and shows all bands, 1- 256. No averaging or amplification has
been applied.
Output Image
The image graph after the filter
Output image spectral graph after being filtered
Parameter Name:
TO
This is the image after the filter. The amplification is clear
immediately from the change in scale necessary to show the new
values. All differences have been amplified, but smaller differences
have increased more significantly than large differences.
