This program accepts a user-defined boxcar and loops
through the input image. It finds the median pixel
value in the boxcar, and sets the output center pixel
to that median value. This will acheive a
"blurring" effect, similar to the lowpass filter.
This will determine how many samples the boxcar will
have. This value must be odd and cannot exceed
twice the number of samples in the cube. Note that
the larger the boxcar size, the slower the program
will run. The size of the boxcar will also have an
impact on the blurring effect. The larger the boxcar,
the greater the blurring.
This will determine how many lines the boxcar will
have. This value must be odd and cannot exceed
twice the number of lines in the cube. Note that
the larger the boxcar size, the slower the program
will run. The size of the boxcar will also have an
impact on the blurring effect. The larger the boxcar,
the greater the blurring.
This value indicates the minimum value of a valid
pixel. If a pixel holds a value below the minimum
value, it will either be filtered or skipped over,
depending on user input in the "Filter Style"
area.
This value indicates the maximum value of a valid
pixel. If a pixel holds a value over the maximum
value, it will either be excluded or included,
depending on user input in the "Filter Style"
area.
This determines what to put in the center pixel,
if there are not enough valid pixels in the boxcar
to meet the minimum requirement. The default is to
replace it with the current value, and the other option
will replace it with NULL.
Type
string
Default
CENTER
Option List:
Option
Brief
Description
CENTER
Center pixel value
This sets the center pixel of the boxcar to the input
value if there are not enough valid pixels to meet
the minimum requirement.
NULL
Pixel value NULL
This sets the center pixel of the boxcar to the special
pixel value of NULL, if there are not enough valid pixels
to meet minimum requirement.
These options determine which pixels are to be included in the filtering
process. ALL filters all pixels, regardless of value, VALID only filters
those pixels with values between LOW and HIGH, and INVALID only
filters those pixels with values outside LOW and HIGH. Note that these
only determine which Non-Special pixels to filter. Also, the median will
only be calculated from pixel values between LOW and HIGH.
Type
string
Default
ALL
Option List:
Option
Brief
Description
ALL
Filter All
This option filters all Non-Special pixels, regardless of value. It only
filters Special Pixels indicated by the user, and the median will only be
calculated from pixel values between LOW and HIGH.
INSIDE
Filter Piexls Between Low and High
This option filters only those pixels with values between LOW and
HIGH, as well as any Special Pixels indicated by the user, and the
median will only be calculated from pixel values between LOW and
HIGH.
OUTSIDE
Filter Pixels Outside Low and High
This option filters only those pixels with values outside LOW and HIGH,
as well as any Special Pixels indicated by the user, and the median will
only be calculated from pixel values between LOW and HIGH.
This determines whether NULL pixels are considered valid for the
purposes of filtering. This, along with the user input in the
"Filter Style" section, will determine whether NULL pixels are
included in the filter.
This determines whether HRS pixels are considered valid for the
purposes of filtering. This, along with the user input in the
"Filter Style" section, will determine whether HRS pixels are
included in the filter.
This determines whether HIS pixels are considered valid for the
purposes of filtering. This, along with the user input in the
"Filter Style" section, will determine whether HIS pixels are
included in the filter.
This determines whether LRS pixels are considered valid for the
purposes of filtering. This, along with the user input in the
"Filter Style" section, will determine whether LRS pixels are
included in the filter.
This determines whether LIS pixels are considered valid for the
purposes of filtering. This, along with the user input in the
"Filter Style" section, will determine whether LIS pixels are
included in the filter.
This demonstrates running the median program on a sample
cube using a 3x3 boxcar.
Command Line
median
from= peaks.cub
to=3x3median.cub
samples=3
lines=3
This demonstrates the commands necessary to run median on
a file named "peaks.cub" with a 3x3 boxcar. The small size of the boxcar
will only produce a slight blur.
GUI Screenshot
median gui
Example GUI
Screenshot of the GUI set to filter all pixels for the image
using a 3x3 boxcar.
Input Image
input cube
Input image before medain filter
Parameter Name:
FROM
This is the original cube. The areas of greatest interest are
those with a great deal of contrast such as edges.
Output Image
median output
Output of 3x3 boxcar median filter
Parameter Name:
TO
This is the image after the filter. You may notice that the whole
image is slightly softer, particularly around areas of sharp
contrast. Due to the small size of the boxcar, the effect is
subtle and difficult to notice.
Example 2
Running median with a 15x15 boxcar
Description
This demonstrates running the median program on a sample
cube using a 15x15 boxcar.
Command Line
median
from= peaks.cub
to=15x15median.cub
samples=15
lines=15
This demonstrates the commands necessary to run median on
a file named "peaks.cub" with a 15x15 boxcar. The large size
of the boxcar produces a marked blurring effect.
GUI Screenshot
median gui
Example GUI
Screenshot of the GUI set to filter all pixels for the image
using a 15x15 boxcar.
Input Image
input cube
Input image before medain filter
Parameter Name:
FROM
This is the original cube. The areas of greatest interest are
those with a great deal of contrast such as edges.
Output Image
median output
Output of 3x3 boxcar median filter
Parameter Name:
TO
This is the output image for a 15x15 boxcar. You will notice
the entire image is noticeably blurrier. It is now virtually
impossible to make out any but the largest of features.
