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ISIS Application Documentation

trimfilter

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Apply a trim filter to a cube

Description
Categories
Groups
Examples
History

Description

This program convolves an NxM boxcar through a cube and trims (or NULLs) pixels. A pixel at the center of the boxcar is trimmed in the output cube if the number of valid pixels inside the boxcar is less than a user specified minimum. Valid pixels are defined as those which are 1) not special pixels and 2) inside the range of the LOW and HIGH parameters. This is a very powerful trimming tool although much thought must be put into the parameters in order to obtain the optimal trimming results.

Categories

Related Applications to Previous Versions of ISIS

This program replaces the following application existing in previous versions of ISIS:

Related Objects and Documents

Applications

Parameter Groups

Files

Name Description
FROM Input file
TO Output trimmed cube

Boxcar Size

Name Description
SAMPLES Number of samples in boxcar
LINES Number of lines in boxcar

Boxcar Restrictions

Name Description
LOW Valid minimum pixel
HIGH Valid maximum pixel
MINOPT Sets minimum to be either a count or a percentage
MINIMUM Minimum boxcar pixel count

Files: FROM

Description

Input cube to filter

Type cube
File Mode input
Filter *.cub

Files: TO

Description

The resultant trimmed cube

Type cube
File Mode output

Boxcar Size: SAMPLES

Description

This is the total number of samples in the boxcar. It must be odd and can not exceed twice the number of samples 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 Size: LINES

Description

This is the total number of lines in the boxcar. It must be odd and can not exceed twice the number of lines 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 Restrictions: 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 boxcar counts.

Type double
Internal Default Use all pixels
Less Than
  • HIGH

Boxcar Restrictions: 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 boxcar counts.

Type double
Internal Default Use all pixels
Greater Than
  • LOW

Boxcar Restrictions: MINOPT

Description

This parameter determines whether the minimum parameter is to be interpreted as a count of pixels, or a percentage of all pixels in the boxcar.

Type string
Default COUNT
Option List:
Option Brief Description
COUNT Minimum valid pixel count This option indicates that the minimum is a minimum count of pixels required for filtering.
PERCENTAGE Minimum valid pixel percentage This option indicates the the minimum parameter is to be interpreted as a percentage of the total pixels in the boxcar.

Boxcar Restrictions: MINIMUM

Description

This is the minimum number of valid pixels which must occur inside the NxM boxcar in order to preserve the output pixel. For example, a 3x5 boxcar has 15 pixels inside. If MINIMUM=10 then the trimming will occur if there are 9 or less valid pixels. A valid pixel is one that is not special (NULL, LIS, etc) and is in the range defined by LOW to HIGH.

Type double
Default 1
Minimum 1 (inclusive)

Examples

Example 1

run a trim filter

Description

This example shows a trimfilter operation.

Command Line

trimfilter f=../IN/lo880.crp.cub t=OUT/trmfltr s=1 li=301 high=241 min=95
trimfilter a Lunar Orbiter image.

GUI Screenshot

trimfilter Gui

Example Gui

Screenshot of GUI with parameters filled in to perform a trimfilter operation on the input image.

Input Image

Input image

Input image for trimfilter

Parameter Name: FROM

This is the input image for the trimfilter example.

Output Image

Output image showing results of the trimfilter application.

Output image for trimfilter

Parameter Name: TO

This is the output image that results.

History

Eric Eliason1988-05-20 Original version
Jeff Anderson2002-08-01 Ported to Isis 3.0
K Teal Thompson2002-12-03 Add example
K Teal Thompson2003-03-28 Make images smaller.
Stuart Sides2003-04-04 Fixed problem with isiscvs not checking in the thumb and image directories.
Kim Sides2003-05-13 Added application test
Stuart Sides2003-05-16 Modified schema location from astogeology... to isis.astrogeology..."
Stuart Sides2003-07-29 Modified filename parameters to be cube parameters where necessary
Brendan George2006-03-20 Added Minopt parameter