Isis 3 Application Documentation
Scale cube down
Overview
Parameters
Example 1
Description
This program will reduce a cube either by averaging pixels or using the
nearest-neighbor algorithm.
Categories
History
Jeff Anderson 1995-11-06
Original version
Tracie Sucharski 2002-10-12
Ported to Isis 3.0, Separated magcube into reduce and enlarge.
Tracie Sucharski 2003-05-13
Read in ons/onl as integers not doubles.
Stuart Sides 2003-05-16
Modified schema location from astogeology... to isis.astrogeology..."
Stuart Sides 2003-07-29
Modified filename parameters to be cube parameters where necessary
Jeff Anderson 2004-07-14
Fixed propagation bug
Tracie Sucharski 2004-07-15
Forget to change ons/onl minimum inclusive values from 1.0 to 1 during the
2003-5-13 change.
Drew Davidson 2005-08-17
Added example
Tracie Sucharski 2006-04-03
Fixed bug in average algorithm, forgot to divide Vper by 100.
Jeff Anderson 2006-09-19
Fixed problems when program ran in batchlist
Sean Crosby 2007-02-28
Program now updates output file's mapping keywords
Steven Koechle 2008-01-23
Changed so if it failed VPER the output cube would get null values.
Now processes cube bands from user input correctly
Steven Lambright 2008-05-13
Removed references to CubeInfo
Steven Koechle 2008-05-15
Added radio button for VPER options to allow original functionaliy.
Parameter Groups
Files
Name
Description
FROM
Input cube to reduce
TO
Output cube
Scaling Parameters
Name
Description
ALGORITHM Algorithm used to reduce image (Average,Nearest neighbor)
SSCALE Sample scaling factor
LSCALE Line scaling factor
ONS Number of samples in output
ONL Number of lines in output
VALIDPER Valid percentage
VPER_REPLACE Replacement method when VPER fails
Files :
FROM
Description
Use this parameter to select the filename. All bands within the file
will be scaled down.
Type
cube
File Mode
input
Filter
*.cub
Files :
TO
Description
This file will contain the results of the shrunken cube.
Type
cube
File Mode
output
Filter
*.cub
Scaling Parameters :
ALGORITHM
Description
This chooses the algorithm used to reduce the image. The possibilities
are: average or nearest-beighbor.
Type
string
Default
AVERAGE
Option List:
Option
Brief
Description
AVERAGE Average surrounding pixels
Use pixel averaging to reduce the image.
NEAREST Nearest-Neighbor
Use nearest neighbor to reduce the image.
Scaling Parameters :
LSCALE
Description
This is the scaling factor for the line direction. For example,
LSCALE=4 will reduce the number of lines by 1/4th.
Type
double
Default
1.0
Minimum
1.0
(inclusive)
Exclusions
Inclusions
Scaling Parameters :
ONS
Description
The number of samples desired in the output cube. This value
must be less than or equal to the number of samples in the input
image.
Type
integer
Minimum
1
(inclusive)
Exclusions
Inclusions
Scaling Parameters :
ONL
Description
The number of lines desired in the output cube. This value
must be less than or equal to the number of lines in the input
image.
Type
integer
Minimum
1
(inclusive)
Exclusions
Inclusions
Scaling Parameters :
VALIDPER
Description
This parameter specifies what percentage of the pixels need to be
valid (non-special pixels). For example, scaling down by a factor
of two results in a 2x2 window (four pixels) being reduced to one
pixel. If VPER is set at 50, then at least two pixels of the four
must be valid (50%). If this criteria is met, the resulting value
of the output pixel will be the average of the valid input pixels.
Otherwise the output pixel will be set to the input pixel which is
closest to the center of the window.
Scaling Parameters :
VPER_REPLACE
Description
When the set VPER variable is not met, this is how the pixel with be
filled.
Type
string
Default
NULL
Option List:
Option
Brief
Description
NULL NULL replacement
Use NULL value when VPER is invalid..
NEAREST Nearest-Neighbor replacement
Use nearest neighbor when VPER is invalid.
Example 1
Reduce the number of samples by a factor of 2
Description
Essentially the opposite of enlarge, this configuration for reduce takes
an image and scales down the samples.
Command Line
reduce
from= peaks.cub
to=reducedPeaks.cub
sscale=2
lscale=1
In this example the sample scale is 2. Note that this implies that the
image will be scaled down by a factor of 2, not scaled up.
GUI Screenshot
reduce gui
Example GUI
Screenshot of the GUI with parameters set to perform a sample
reduction.
Input Image
The image before the filter
Input image before reduce
Parameter Name:
FROM
This is the image as it was taken originally.
Output Image
The image after the filter
Output image after minmax
Parameter Name:
TO
The reduced image. Though it has been scaled down so that it can
be viewed by a web browser, the essential change can still be observed.
The vertical distortion is noticable, and the output cube is 1/2 the
size of the input cube.
